diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..aa724b7
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,15 @@
+*.iml
+.gradle
+/local.properties
+/.idea/caches
+/.idea/libraries
+/.idea/modules.xml
+/.idea/workspace.xml
+/.idea/navEditor.xml
+/.idea/assetWizardSettings.xml
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx
+local.properties
diff --git a/build.gradle.kts b/build.gradle.kts
new file mode 100644
index 0000000..1fcd216
--- /dev/null
+++ b/build.gradle.kts
@@ -0,0 +1,20 @@
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+plugins {
+    alias(libs.plugins.android.application) apply false
+    alias(libs.plugins.jetbrains.kotlin.android) apply false
+    alias(libs.plugins.android.library) apply false
+    alias(libs.plugins.google.ksp) apply false
+}
+
+subprojects {
+    afterEvaluate {
+        // Load configuration file (if it exists)
+        val jacocoFile = file("../jacoco.gradle")
+        if (jacocoFile.exists()) {
+            apply(from = jacocoFile)
+            println("jacoco applied.")
+        } else {
+            println("jacoco file not found.")
+        }
+    }
+}
\ No newline at end of file
diff --git a/gradle.properties b/gradle.properties
new file mode 100644
index 0000000..20e2a01
--- /dev/null
+++ b/gradle.properties
@@ -0,0 +1,23 @@
+# Project-wide Gradle settings.
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+# Specifies the JVM arguments used for the daemon process.
+# The setting is particularly useful for tweaking memory settings.
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
+# When configured, Gradle will run in incubating parallel mode.
+# This option should only be used with decoupled projects. For more details, visit
+# https://developer.android.com/r/tools/gradle-multi-project-decoupled-projects
+# org.gradle.parallel=true
+# AndroidX package structure to make it clearer which packages are bundled with the
+# Android operating system, and which are packaged with your app's APK
+# https://developer.android.com/topic/libraries/support-library/androidx-rn
+android.useAndroidX=true
+# Kotlin code style for this project: "official" or "obsolete":
+kotlin.code.style=official
+# Enables namespacing of each library's R class so that its R class includes only the
+# resources declared in the library itself and none from the library's dependencies,
+# thereby reducing the size of the R class for that library
+android.nonTransitiveRClass=true
\ No newline at end of file
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
new file mode 100644
index 0000000..8bf23d7
--- /dev/null
+++ b/gradle/libs.versions.toml
@@ -0,0 +1,49 @@
+[versions]
+agp = "8.5.1"
+kotlin = "1.9.21"
+coreKtx = "1.13.1"
+junit = "4.13.2"
+junitVersion = "1.2.1"
+espressoCore = "3.6.1"
+appcompat = "1.7.0"
+material = "1.12.0"
+mockitoCore = "5.14.2"
+web3j = "4.8.9-android"
+gson = "2.10"
+retrofit2 = "2.9.0"
+okhttp3-logging-interceptor = "4.11.0"
+kotlinx-coroutines-test = "1.8.1"
+moshi = "1.15.1"
+ksp = "1.9.21-1.0.15"
+androidx-credentials = "1.3.0-alpha01"
+dokka = "1.9.20"
+
+
+[libraries]
+androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
+junit = { group = "junit", name = "junit", version.ref = "junit" }
+androidx-junit = { group = "androidx.test.ext", name = "junit", version.ref = "junitVersion" }
+androidx-espresso-core = { group = "androidx.test.espresso", name = "espresso-core", version.ref = "espressoCore" }
+androidx-appcompat = { group = "androidx.appcompat", name = "appcompat", version.ref = "appcompat" }
+material = { group = "com.google.android.material", name = "material", version.ref = "material" }
+mockito-android = { module = "org.mockito:mockito-android", version.ref = "mockitoCore" }
+mockito-core = { module = "org.mockito:mockito-core", version = "5.14.2" }
+web3j = { group = "org.web3j", name = "core", version.ref = "web3j" }
+retrofit2-retrofit = { group = "com.squareup.retrofit2", name = "retrofit", version.ref = "retrofit2" }
+retrofit2-converter-gson = { group = "com.squareup.retrofit2", name = "converter-gson", version.ref = "retrofit2" }
+gson = { group = "com.google.code.gson", name = "gson", version.ref = "gson" }
+okhttp3-logging-interceptor = { group = "com.squareup.okhttp3", name = "logging-interceptor", version.ref = "okhttp3-logging-interceptor" }
+kotlinx-coroutines-test = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-test", version.ref = "kotlinx-coroutines-test" }
+moshi-kotlin = { group = "com.squareup.moshi", name = "moshi-kotlin", version.ref = "moshi" }
+moshi-ksp = { group = "com.squareup.moshi", name = "moshi-kotlin-codegen", version.ref = "moshi" }
+retrofit2-converter-moshi = { group = "com.squareup.retrofit2", name = "converter-moshi", version.ref = "retrofit2" }
+androidx-credentials = { group = "androidx.credentials", name = "credentials", version.ref = "androidx-credentials" }
+androidx-credentials-auth = { group = "androidx.credentials", name = "credentials-play-services-auth", version.ref = "androidx-credentials" }
+
+
+[plugins]
+android-application = { id = "com.android.application", version.ref = "agp" }
+jetbrains-kotlin-android = { id = "org.jetbrains.kotlin.android", version.ref = "kotlin" }
+android-library = { id = "com.android.library", version.ref = "agp" }
+google-ksp = { id = "com.google.devtools.ksp", version.ref = "ksp" }
+jetbrains-dokka = { id = "org.jetbrains.dokka", version.ref = "dokka" }
\ No newline at end of file
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..e708b1c
Binary files /dev/null and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..e26cf30
--- /dev/null
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,6 @@
+#Mon Sep 02 21:26:25 CST 2024
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
new file mode 100755
index 0000000..4f906e0
--- /dev/null
+++ b/gradlew
@@ -0,0 +1,185 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
new file mode 100644
index 0000000..ac1b06f
--- /dev/null
+++ b/gradlew.bat
@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/lib/.gitignore b/lib/.gitignore
new file mode 100644
index 0000000..42afabf
--- /dev/null
+++ b/lib/.gitignore
@@ -0,0 +1 @@
+/build
\ No newline at end of file
diff --git a/lib/build.gradle.kts b/lib/build.gradle.kts
new file mode 100644
index 0000000..b85b27e
--- /dev/null
+++ b/lib/build.gradle.kts
@@ -0,0 +1,198 @@
+import org.jetbrains.dokka.DokkaConfiguration.Visibility
+import org.jetbrains.dokka.gradle.DokkaTask
+import java.io.FileInputStream
+import java.net.URI
+import java.util.Properties
+
+plugins {
+    alias(libs.plugins.android.library)
+    alias(libs.plugins.jetbrains.kotlin.android)
+    alias(libs.plugins.google.ksp)
+    alias(libs.plugins.jetbrains.dokka)
+    id("maven-publish")
+    id("com.github.ben-manes.versions") version "0.46.0"
+}
+
+extra.apply {
+    set("versionMajor", 0)
+    set("versionMedium", 0)
+    set("versionMinorPublished", 204) // should increment after public release
+    set("libraryId", libraryId())
+    set("libraryGroupId", libraryId())
+    set("libraryArtifactId", libraryArtifactId())
+    set("defaultRepo", "")
+}
+
+fun libraryArtifactId(): String {
+    return if (project.hasProperty("LIB_ART_ID")) {
+        project.property("LIB_ART_ID") as String
+    } else {
+        "core"
+    }
+}
+
+fun libraryId(): String {
+    return if (project.hasProperty("LIB_ID")) {
+        project.property("LIB_ID") as String
+    } else {
+        "circle.modularwallets"
+    }
+}
+
+fun buildNum(): Int {
+    return if (project.hasProperty("BUILD_NUM")) {
+        project.property("BUILD_NUM").toString().toInt()
+    } else {
+        0
+    }
+}
+
+fun majorNumber(): Int {
+    return if (project.hasProperty("MAJOR_NUMBER")) {
+        project.property("MAJOR_NUMBER").toString().toInt()
+    } else {
+        extra["versionMajor"] as Int
+    }
+}
+
+fun isInternalBuild(): Boolean {
+    return majorNumber() == 0
+
+}
+
+fun apiVersion(): String {
+    return if (isInternalBuild()) {
+        "${majorNumber()}.${extra["versionMedium"]}.${extra["versionMinorPublished"]}-${buildNum()}" // internal build's buildNum is action build number
+    } else {
+        "${majorNumber()}.${extra["versionMedium"]}.${buildNum()}" // release build's buildNum is extracted from the git tag
+    }
+}
+
+fun libraryVersion(): String {
+    val ver = apiVersion()
+    return if (project.hasProperty("SNAPSHOT")) {
+        "${ver}-SNAPSHOT"
+    } else {
+        ver
+    }
+}
+
+fun nexusRepo(): String {
+    return if (project.hasProperty("NEXUS_REPO")) {
+        project.property("NEXUS_REPO") as String
+    } else {
+        extra["defaultRepo"] as String
+    }
+}
+
+fun nexusUsername(): String {
+    return if (project.hasProperty("NEXUS_USERNAME")) {
+        project.property("NEXUS_USERNAME") as String
+    } else {
+        ""
+    }
+}
+
+fun nexusPassword(): String {
+    return if (project.hasProperty("NEXUS_PASSWORD")) {
+        project.property("NEXUS_PASSWORD") as String
+    } else {
+        ""
+    }
+}
+
+android {
+    namespace = "com.circle.modularwallets.core"
+    compileSdk = 34
+
+    defaultConfig {
+        minSdk = 28
+        version = libraryVersion()
+        buildConfigField("String", "version", "\"${version}\"")
+        buildConfigField("boolean", "INTERNAL_BUILD", "${isInternalBuild()}")
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+        testInstrumentationRunnerArguments += mapOf(
+            "notPackage" to "com.circle.modularwallets.core.manual"
+        )
+    }
+
+    buildTypes {
+        debug {
+            enableAndroidTestCoverage = true
+            enableUnitTestCoverage = true
+        }
+        release {
+            isMinifyEnabled = true
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+        }
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility = JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+    buildFeatures {
+        buildConfig = true
+    }
+}
+
+dependencies {
+    ksp(libs.moshi.ksp)
+    implementation(libs.androidx.credentials)
+    implementation(libs.androidx.credentials.auth)
+    implementation(libs.retrofit2.converter.moshi)
+    implementation(libs.moshi.kotlin)
+    implementation(libs.web3j)
+    implementation(libs.retrofit2.retrofit)
+    implementation(libs.retrofit2.converter.gson)
+    implementation(libs.gson)
+    implementation(libs.okhttp3.logging.interceptor)
+    implementation(libs.androidx.core.ktx)
+    implementation(libs.androidx.appcompat)
+    implementation(libs.material)
+    testImplementation(libs.junit)
+    androidTestImplementation(libs.androidx.junit)
+    androidTestImplementation(libs.androidx.espresso.core)
+    androidTestImplementation(libs.kotlinx.coroutines.test)
+    androidTestImplementation(libs.web3j)
+
+    testImplementation(libs.junit)
+    androidTestImplementation(libs.androidx.junit)
+    androidTestImplementation(libs.androidx.espresso.core)
+
+    // Add Mockito dependency
+    testImplementation(libs.mockito.core)
+    testImplementation(libs.mockito.android)
+    androidTestImplementation(libs.mockito.core)
+    androidTestImplementation(libs.mockito.android)
+}
+
+afterEvaluate {
+    configure<PublishingExtension> {
+        publications {
+            create<MavenPublication>("release") {
+                from(components["release"])
+                groupId = extra["libraryGroupId"] as String
+                artifactId = extra["libraryArtifactId"] as String
+                version = libraryVersion()
+            }
+        }
+
+        repositories {
+            maven {
+                name = "CircleModularwallets"
+                url = URI(nexusRepo())
+                isAllowInsecureProtocol = true
+                credentials {
+                    username = nexusUsername()
+                    password = nexusPassword()
+                }
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/lib/proguard-rules.pro b/lib/proguard-rules.pro
new file mode 100644
index 0000000..0e8c6da
--- /dev/null
+++ b/lib/proguard-rules.pro
@@ -0,0 +1,38 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile
+# https://developer.android.com/identity/sign-in/credential-manager#proguard
+-if class androidx.credentials.CredentialManager
+-keep class androidx.credentials.playservices.** {
+  *;
+}
+-keep public class com.circle.modularwallets.core.** {
+    public *;
+}
+-keep class com.circle.modularwallets.core.apis.rp.PublicKeyCredentialCreationOptions { *; }
+-keep class com.circle.modularwallets.core.apis.rp.AuthenticatorSelectionCriteria { *; }
+-keep class com.circle.modularwallets.core.apis.rp.PublicKeyCredentialRpEntity { *; }
+-keep class com.circle.modularwallets.core.apis.rp.PublicKeyCredentialUserEntity { *; }
+-keep class com.circle.modularwallets.core.apis.rp.PublicKeyCredentialRequestOptions { *; }
+-keep class com.circle.modularwallets.core.apis.rp.PublicKeyCredentialDescriptor { *; }
+-keep class com.circle.modularwallets.core.apis.rp.PublicKeyCredentialParameters { *; }
+-keep class androidx.credentials.** { *; }
+-keep class org.json.** { *; }
\ No newline at end of file
diff --git a/lib/src/main/AndroidManifest.xml b/lib/src/main/AndroidManifest.xml
new file mode 100644
index 0000000..294dbaa
--- /dev/null
+++ b/lib/src/main/AndroidManifest.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <uses-permission android:name="android.permission.INTERNET" />
+</manifest>
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/accounts/Account.kt b/lib/src/main/java/com/circle/modularwallets/core/accounts/Account.kt
new file mode 100644
index 0000000..7fe292c
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/accounts/Account.kt
@@ -0,0 +1,63 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.accounts
+
+import android.content.Context
+
+/**
+ * Abstract class representing an account.
+ *
+ * @param T The type of the signed data.
+ */
+abstract class Account<T> {
+
+    /**
+     * Retrieves the address of the account.
+     *
+     * @return The address of the account.
+     */
+    abstract fun getAddress(): String
+
+    /**
+     * Signs the given hex data.
+     *
+     * @param context The context in which the signing operation is performed.
+     * @param hex The hex data to sign.
+     * @return The signed data of type T.
+     */
+    abstract suspend fun sign(context: Context, hex: String): T
+
+    /**
+     * Signs the given message.
+     *
+     * @param context The context in which the signing operation is performed.
+     * @param message The message to sign.
+     * @return The signed message of type T.
+     */
+    abstract suspend fun signMessage(context: Context, message: String): T
+
+    /**
+     * Signs the given typed data.
+     *
+     * @param context The context in which the signing operation is performed.
+     * @param typedData The typed data to sign.
+     * @return The signed typed data of type T.
+     */
+    abstract suspend fun signTypedData(context: Context, typedData: String): T
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/accounts/CircleSmartAccount.kt b/lib/src/main/java/com/circle/modularwallets/core/accounts/CircleSmartAccount.kt
new file mode 100644
index 0000000..16a0bcf
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/accounts/CircleSmartAccount.kt
@@ -0,0 +1,592 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.accounts
+
+import android.content.Context
+import com.circle.modularwallets.core.BuildConfig
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.circle.modularwallets.core.apis.modular.ModularApiImpl
+import com.circle.modularwallets.core.apis.modular.ModularWallet
+import com.circle.modularwallets.core.apis.modular.ScaConfiguration
+import com.circle.modularwallets.core.apis.modular.getCreateWalletReq
+import com.circle.modularwallets.core.apis.public.PublicApiImpl
+import com.circle.modularwallets.core.apis.util.UtilApiImpl
+import com.circle.modularwallets.core.clients.Client
+import com.circle.modularwallets.core.constants.CIRCLE_SMART_ACCOUNT_VERSION
+import com.circle.modularwallets.core.constants.CIRCLE_SMART_ACCOUNT_VERSION_V1
+import com.circle.modularwallets.core.constants.CIRCLE_WEIGHTED_WEB_AUTHN_MULTISIG_PLUGIN
+import com.circle.modularwallets.core.constants.EIP712_PREFIX
+import com.circle.modularwallets.core.constants.FACTORY
+import com.circle.modularwallets.core.constants.PUBLIC_KEY_OWN_WEIGHT
+import com.circle.modularwallets.core.constants.REPLAY_SAFE_HASH_V1
+import com.circle.modularwallets.core.constants.SALT
+import com.circle.modularwallets.core.constants.STUB_SIGNATURE
+import com.circle.modularwallets.core.constants.THRESHOLD_WEIGHT
+import com.circle.modularwallets.core.models.EncodeCallDataArg
+import com.circle.modularwallets.core.models.EntryPoint
+import com.circle.modularwallets.core.models.EstimateUserOperationGasResult
+import com.circle.modularwallets.core.models.SignResult
+import com.circle.modularwallets.core.models.UserOperation
+import com.circle.modularwallets.core.models.UserOperationV07
+import com.circle.modularwallets.core.transports.Transport
+import com.circle.modularwallets.core.utils.FunctionParameters
+import com.circle.modularwallets.core.utils.NonceManager
+import com.circle.modularwallets.core.utils.NonceManagerSource
+import com.circle.modularwallets.core.utils.abi.encodeAbiParameters
+import com.circle.modularwallets.core.utils.abi.encodeCallData
+import com.circle.modularwallets.core.utils.abi.encodePacked
+import com.circle.modularwallets.core.utils.data.concat
+import com.circle.modularwallets.core.utils.data.pad
+import com.circle.modularwallets.core.utils.data.slice
+import com.circle.modularwallets.core.utils.encoding.bytesToHex
+import com.circle.modularwallets.core.utils.encoding.stringToHex
+import com.circle.modularwallets.core.utils.encoding.toBytes
+import com.circle.modularwallets.core.utils.encoding.toSha3Bytes
+import com.circle.modularwallets.core.utils.signature.hashMessage
+import com.circle.modularwallets.core.utils.signature.hashTypedData
+import com.circle.modularwallets.core.utils.signature.parseP256Signature
+import com.circle.modularwallets.core.utils.smartAccount.getMinimumVerificationGasLimit
+import com.circle.modularwallets.core.utils.userOperation.getUserOperationHash
+import com.circle.modularwallets.core.utils.userOperation.parseFactoryAddressAndData
+import org.web3j.abi.FunctionEncoder
+import org.web3j.abi.TypeReference
+import org.web3j.abi.datatypes.Address
+import org.web3j.abi.datatypes.Bool
+import org.web3j.abi.datatypes.DynamicArray
+import org.web3j.abi.datatypes.DynamicBytes
+import org.web3j.abi.datatypes.DynamicStruct
+import org.web3j.abi.datatypes.StaticStruct
+import org.web3j.abi.datatypes.Type
+import org.web3j.abi.datatypes.Utf8String
+import org.web3j.abi.datatypes.generated.Bytes32
+import org.web3j.abi.datatypes.generated.Uint256
+import org.web3j.abi.datatypes.generated.Uint8
+import org.web3j.crypto.Hash
+import org.web3j.utils.Numeric
+import java.math.BigInteger
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+import java.util.TimeZone
+
+internal suspend fun getModularWalletAddress(
+    transport: Transport, hexPublicKey: String, version: String, name: String? = null
+): ModularWallet {
+    val (x, y) = parseP256Signature(hexPublicKey)
+    val wallet =
+        ModularApiImpl.getAddress(
+            transport,
+            getCreateWalletReq(x.toString(), y.toString(), version, name)
+        )
+    return wallet
+}
+
+internal suspend fun getComputeWallet(
+    client: Client,
+    owner: Account<SignResult>,
+    version: String
+): ModularWallet {
+    return ModularWallet(
+        address = getAddressFromWebAuthnOwner(client.transport, owner.getAddress()),
+        scaConfiguration = ScaConfiguration(
+            scaCore = version,
+        ),
+    )
+}
+
+internal fun getCurrentDateTime(): String {
+    val dateFormat = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", Locale.getDefault())
+    dateFormat.timeZone = TimeZone.getTimeZone("UTC")
+    val currentDate = Date()
+    return dateFormat.format(currentDate)
+}
+
+internal fun getDefaultWalletName(): String {
+    return "passkey-${getCurrentDateTime()}"
+}
+
+/**
+ * Creates a Circle smart account.
+ *
+ * @param client The client used to interact with the blockchain.
+ * @param owner The owner account associated with the Circle smart account.
+ * @param version The version of the Circle smart account. Default is "circle_passkey_account_v1".
+ * @param name The wallet name assigned to the newly registered account defaults to the passkey username provided by the end user.
+ * @return The created Circle smart account.
+ */
+
+@Throws(Exception::class)
+@JvmOverloads
+suspend fun toCircleSmartAccount(
+    client: Client,
+    owner: Account<SignResult>,
+    version: String = CIRCLE_SMART_ACCOUNT_VERSION_V1,
+    name: String = getDefaultWalletName()
+): CircleSmartAccount {
+    val actualVersion = CIRCLE_SMART_ACCOUNT_VERSION[version] ?: version
+    val wallet =
+        try {
+            getModularWalletAddress(client.transport, owner.getAddress(), actualVersion, name)
+        } catch (e: Throwable) {
+            if (BuildConfig.INTERNAL_BUILD) {
+                getComputeWallet(client, owner, actualVersion)
+            } else {
+                throw e
+            }
+        }
+    val account = CircleSmartAccount(
+        client, owner, wallet
+    )
+    return account
+}
+
+/**
+ * Class representing a Circle smart account.
+ *
+ * @param client The client used to interact with the blockchain.
+ * @param owner The owner account associated with the Circle Smart account.
+ * @param wallet The response containing the created wallet information.
+ * @param entryPoint The entry point for the smart account. Default is EntryPoint.V07.
+ */
+
+class CircleSmartAccount(
+    client: Client,
+    private val owner: Account<SignResult>,
+    internal val wallet: ModularWallet,
+    entryPoint: EntryPoint = EntryPoint.V07
+) : SmartAccount(client, entryPoint) {
+    private var deployed = false
+    private val nonceManager = NonceManager(object : NonceManagerSource {
+        override fun get(parameters: FunctionParameters): BigInteger {
+            return BigInteger.valueOf(System.currentTimeMillis())
+        }
+
+        override fun set(parameters: FunctionParameters, nonce: BigInteger) {
+        }
+    })
+
+    /**
+     * Configuration for the user operation.
+     */
+    override var userOperation: UserOperationConfiguration? =
+        UserOperationConfiguration { userOperation ->
+            val minimumVerificationGasLimit =
+                getMinimumVerificationGasLimit(isDeployed(), client.chain.chainId)
+            EstimateUserOperationGasResult(
+                verificationGasLimit = minimumVerificationGasLimit
+                    .max(userOperation.verificationGasLimit ?: BigInteger.ZERO)
+            )
+        }
+
+    /**
+     * Returns the address of the Circle smart account.
+     *
+     * @return The address of the Circle smart account.
+     */
+    override fun getAddress(): String {
+        return wallet.address
+    }
+
+    /**
+     * Encodes the given call data arguments.
+     *
+     * @param args The call data arguments to encode.
+     * @return The encoded call data.
+     */
+    override fun encodeCalls(args: Array<EncodeCallDataArg>): String {
+        return encodeCallData(args)
+    }
+
+    /**
+     * Returns the factory arguments if the account is not deployed.
+     *
+     * @return The factory arguments or null if already deployed.
+     */
+    override suspend fun getFactoryArgs(): Pair<String, String>? {
+        if (isDeployed()) {
+            return null
+        }
+        wallet.scaConfiguration.initCode?.let {
+            return parseFactoryAddressAndData(it)
+        }
+        return Pair(FACTORY.address, getFactoryData(owner.getAddress()))
+    }
+
+    /**
+     * Checks if the account is deployed.
+     *
+     * @return True if the account is deployed, false otherwise.
+     */
+
+    @Throws(Exception::class)
+    suspend fun isDeployed(): Boolean {
+        if (deployed) {
+            return true
+        }
+        try {
+            val byteCode = PublicApiImpl.getCode(client.transport, getAddress())
+            deployed = Numeric.hexStringToByteArray(byteCode).isNotEmpty()
+            return deployed
+        } catch (e: Throwable) {
+            return false
+        }
+    }
+
+    /**
+     * Returns the nonce for the Circle smart account.
+     *
+     * @param key Optional key to retrieve the nonce for.
+     * @return The nonce of the Circle smart account.
+     */
+
+    @Throws(Exception::class)
+    override suspend fun getNonce(key: BigInteger?): BigInteger {
+        val notNullKey =
+            key ?: nonceManager.consume(FunctionParameters(getAddress(), client.chain.chainId))
+        val nonce =
+            UtilApiImpl.getNonce(client.transport, getAddress(), entryPoint.address, notNullKey)
+        return nonce
+    }
+
+    /**
+     * Returns the stub signature for the given user operation.
+     *
+     * @param userOp The user operation to retrieve the stub signature for. Type T must be the subclass of UserOperation.
+     * @return The stub signature.
+     */
+    override fun <T : UserOperation> getStubSignature(userOp: T): String {
+        return STUB_SIGNATURE
+    }
+
+    /**
+     * Signs the given hex data.
+     *
+     * @param context The context used to launch framework UI flows ; use an activity context to make sure the UI will be launched within the same task stack.
+     * @param hex The hex data to sign.
+     * @return The signed data.
+     */
+    @ExcludeFromGeneratedCCReport
+    @Throws(Exception::class)
+    override suspend fun sign(context: Context, hex: String): String {
+        val digest = toSha3Bytes(hex)
+        val hash = getReplaySafeHash(
+            client.chain.chainId, getAddress(), bytesToHex(digest)
+        )
+        val signResult = owner.sign(context, hash)
+        val signature = encodePackedForSignature(
+            signResult,
+            owner.getAddress(),
+            false,
+        )
+        return signature
+    }
+
+    /**
+     * Signs the given message.
+     *
+     * @param context The context used to launch framework UI flows ; use an activity context to make sure the UI will be launched within the same task stack.
+     * @param message The message to sign.
+     * @return The signed message.
+     */
+    @ExcludeFromGeneratedCCReport
+    @Throws(Exception::class)
+    override suspend fun signMessage(context: Context, message: String): String {
+        val digest = toSha3Bytes(hashMessage(message.toByteArray()))
+        val hash = getReplaySafeHash(
+            client.chain.chainId, getAddress(), bytesToHex(digest)
+        )
+        val signResult = owner.sign(context, hash)
+        val signature = encodePackedForSignature(
+            signResult,
+            owner.getAddress(),
+            false,
+        )
+        return signature
+    }
+
+    /**
+     * Signs the given typed data.
+     *
+     * @param context The context used to launch framework UI flows ; use an activity context to make sure the UI will be launched within the same task stack.
+     * @param typedData The typed data to sign.
+     * @return The signed typed data.
+     */
+    @ExcludeFromGeneratedCCReport
+    @Throws(Exception::class)
+    override suspend fun signTypedData(context: Context, typedData: String): String {
+        val digest = toSha3Bytes(hashTypedData(typedData))
+        val hash = getReplaySafeHash(
+            client.chain.chainId, getAddress(), bytesToHex(digest)
+        )
+        val signResult = owner.sign(context, hash)
+        val signature = encodePackedForSignature(
+            signResult,
+            owner.getAddress(),
+            false,
+        )
+        return signature
+    }
+
+    /**
+     * Signs the given user operation.
+     *
+     * @param context The context used to launch framework UI flows ; use an activity context to make sure the UI will be launched within the same task stack.
+     * @param chainId The chain ID for the user operation. Default is the chain ID of the client.
+     * @param userOp The user operation to sign.
+     * @return The signed user operation.
+     */
+    @ExcludeFromGeneratedCCReport
+    @Throws(Exception::class)
+    override suspend fun signUserOperation(
+        context: Context, chainId: Long, userOp: UserOperationV07
+    ): String {
+        userOp.sender = getAddress()
+        val userOpHash = getUserOperationHash(chainId, userOp = userOp)
+        val hash = hashMessage(userOpHash)
+        val signResult = owner.sign(context, hash)
+        val signature = encodePackedForSignature(
+            signResult,
+            owner.getAddress(),
+            true,
+        )
+        return signature
+    }
+
+    /**
+     * Returns the initialization code for the Circle smart account.
+     *
+     * @return The initialization code.
+     */
+    override suspend fun getInitCode(): String? {
+        return wallet.getInitCode()
+    }
+
+}
+
+internal fun getReplaySafeHash(
+    chainId: Long,
+    account: String,
+    hash: String,
+    verifyingContract: String = CIRCLE_WEIGHTED_WEB_AUTHN_MULTISIG_PLUGIN.address,
+): String {
+    val prefix = Numeric.hexStringToByteArray(EIP712_PREFIX)
+    val domainSeparatorTypeHash =
+        toSha3Bytes(REPLAY_SAFE_HASH_V1.domainSeparatorType)
+
+    val domainSeparator = toSha3Bytes(
+        encodeAbiParameters(
+            listOf(
+                Bytes32(domainSeparatorTypeHash),
+                Bytes32(getModuleIdHash()),
+                Uint256(chainId),
+                Address(verifyingContract),
+                Bytes32(pad(toBytes(account), isRight = true)),
+            )
+        )
+    )
+
+    val structHash = toSha3Bytes(
+        encodeAbiParameters(
+            listOf(
+                Bytes32(getModuleTypeHash()),
+                Bytes32(Numeric.hexStringToByteArray(hash))
+            )
+        )
+    )
+    return bytesToHex(
+        Hash.sha3(
+            concat(
+                prefix,
+                domainSeparator,
+                structHash
+            )
+        )
+    )
+}
+
+internal fun getModuleIdHash(): ByteArray {
+    return toSha3Bytes(
+        encodePacked(
+            listOf<Type<*>>(
+                Utf8String(REPLAY_SAFE_HASH_V1.name),
+                Utf8String(REPLAY_SAFE_HASH_V1.version),
+            )
+        )
+    )
+}
+
+internal fun getModuleTypeHash(): ByteArray {
+    return toSha3Bytes(
+        REPLAY_SAFE_HASH_V1.moduleType
+    )
+}
+
+internal fun encodePackedForSignature(
+    signResult: SignResult,
+    publicKey: String,
+    hasUserOpGas: Boolean,
+): String {
+    val (x, y) = parseP256Signature(publicKey)
+    val sender = getSender(x, y)
+
+    val sigBytes = encodeWebAuthnSigDynamicPart(signResult)
+    val formattedSender = getFormattedSender(sender)
+    val sigType: Long = if (hasUserOpGas) 34 else 2
+    val encoded =
+        encodePacked(
+            listOf<Type<*>>(
+                Bytes32(formattedSender),
+                Uint256(65), // dynamicPos
+                Uint8(sigType),
+                Uint256(sigBytes.size.toLong()),
+                DynamicBytes(sigBytes),
+            )
+        )
+
+    return encoded
+}
+
+internal fun encodeWebAuthnSigDynamicPart(signResult: SignResult): ByteArray {
+    val (r, s) = parseP256Signature(signResult.signature)
+    val encoded = encodeParametersWebAuthnSigDynamicPart(
+        signResult.webAuthn.authenticatorData,
+        signResult.webAuthn.clientDataJSON,
+        signResult.webAuthn.challengeIndex.toLong(),
+        signResult.webAuthn.typeIndex.toLong(),
+        true,
+        r,
+        s
+    )
+    return Numeric.hexStringToByteArray(encoded)
+}
+
+internal fun encodeParametersWebAuthnSigDynamicPart(
+    authenticatorData: String,
+    clientDataJSON: String,
+    challengeIndex: Long,
+    typeIndex: Long,
+    requireUserVerification: Boolean,
+    r: BigInteger,
+    s: BigInteger
+): String {
+    val encoded = encodeAbiParameters(
+        listOf<Type<*>>(
+            DynamicStruct(
+                DynamicStruct(
+                    DynamicBytes(Numeric.hexStringToByteArray(authenticatorData)),
+                    DynamicBytes(Numeric.hexStringToByteArray(stringToHex(clientDataJSON))),
+                    Uint256(challengeIndex),
+                    Uint256(typeIndex),
+                    Bool(requireUserVerification),
+                ),
+                Uint256(r),
+                Uint256(s),
+            )
+        )
+    )
+    return encoded
+}
+
+internal fun getFormattedSender(sender: String): ByteArray {
+    return Numeric.hexStringToByteArray(pad(slice(sender, 2)))
+}
+
+internal fun getPluginInstallParams(x: BigInteger, y: BigInteger): String {
+    val encoded = encodeAbiParameters(
+        listOf(
+            DynamicArray(Address::class.java), DynamicArray(Uint256::class.java), DynamicArray(
+                StaticStruct::class.java,
+                StaticStruct(
+                    Uint256(x),
+                    Uint256(y),
+                ),
+            ), DynamicArray(
+                Uint256::class.java, Uint256(PUBLIC_KEY_OWN_WEIGHT)
+            ), Uint256(THRESHOLD_WEIGHT)
+        )
+    )
+    return encoded
+}
+
+internal fun getInitializeUpgradableMSCAParams(x: BigInteger, y: BigInteger): String {
+    val pluginInstallParams = getPluginInstallParams(x, y)
+    val encoded = encodeAbiParameters(
+        listOf(
+            DynamicArray(
+                Address::class.java,
+                Address(CIRCLE_WEIGHTED_WEB_AUTHN_MULTISIG_PLUGIN.address),
+            ),
+            DynamicArray(
+                Bytes32::class.java,
+                Bytes32(CIRCLE_WEIGHTED_WEB_AUTHN_MULTISIG_PLUGIN.manifestHash),
+            ),
+            DynamicArray(
+                DynamicBytes::class.java,
+                DynamicBytes(Numeric.hexStringToByteArray(pluginInstallParams)),
+            ),
+        )
+    )
+    return encoded
+}
+
+internal fun getSender(x: BigInteger, y: BigInteger): String {
+    val encoded = getSenderParams(x, y)
+    return Hash.sha3(encoded)
+}
+
+internal fun getSenderParams(x: BigInteger, y: BigInteger): String {
+    return encodeAbiParameters(
+        listOf(
+            Uint256(x),
+            Uint256(y),
+        )
+    )
+}
+
+internal fun getFactoryData(publicKey: String): String {
+    val (x, y) = parseP256Signature(publicKey)
+    val sender = getSender(x, y)
+    val initializeUpgradableMSCAParams = getInitializeUpgradableMSCAParams(x, y)
+    val function = org.web3j.abi.datatypes.Function(
+        "createAccount", listOf(
+            Bytes32(Numeric.hexStringToByteArray(sender)),
+            Bytes32(SALT),
+            DynamicBytes(Numeric.hexStringToByteArray(initializeUpgradableMSCAParams)),
+        ), listOf<TypeReference<*>>(object : TypeReference<Address>() {})
+    )
+    val factoryData = FunctionEncoder.encode(function)
+    return factoryData
+}
+
+internal suspend fun getAddressFromWebAuthnOwner(transport: Transport, publicKey: String): String {
+    val (x, y) = parseP256Signature(publicKey)
+    val sender = getSender(x, y)
+    val initializeUpgradableMSCAParams = getInitializeUpgradableMSCAParams(x, y)
+
+    /** address, mixedSalt */
+    val result = UtilApiImpl.getAddress(
+        transport,
+        FACTORY.address,
+        Numeric.hexStringToByteArray(sender),
+        SALT,
+        Numeric.hexStringToByteArray(initializeUpgradableMSCAParams)
+    )
+    return result.first
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/accounts/SmartAccount.kt b/lib/src/main/java/com/circle/modularwallets/core/accounts/SmartAccount.kt
new file mode 100644
index 0000000..34ba2b6
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/accounts/SmartAccount.kt
@@ -0,0 +1,130 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.accounts
+
+import android.content.Context
+import com.circle.modularwallets.core.clients.Client
+import com.circle.modularwallets.core.models.EncodeCallDataArg
+import com.circle.modularwallets.core.models.EntryPoint
+import com.circle.modularwallets.core.models.EstimateUserOperationGasResult
+import com.circle.modularwallets.core.models.UserOperation
+import com.circle.modularwallets.core.models.UserOperationV07
+import java.math.BigInteger
+
+/**
+ * A Smart Account is an account whose implementation resides in a Smart Contract, and implements the ERC-4337 interface.
+ *
+ * @param client The client used to interact with the blockchain.
+ * @param entryPoint The entry point for the smart account.
+ */
+abstract class SmartAccount(val client: Client, val entryPoint: EntryPoint) {
+
+    /**
+     * Configuration for the user operation.
+     */
+    open var userOperation: UserOperationConfiguration? = null
+
+    /**
+     * Returns the address of the account.
+     *
+     * @return The address of the smart account.
+     */
+    abstract fun getAddress(): String
+
+    /**
+     * Encodes the given call data arguments.
+     *
+     * @param args The call data arguments to encode.
+     * @return The encoded call data.
+     */
+    abstract fun encodeCalls(args: Array<EncodeCallDataArg>): String
+
+    /**
+     * Returns the factory arguments for the smart account.
+     *
+     * @return A pair containing the factory arguments.
+     */
+    abstract suspend fun getFactoryArgs(): Pair<String, String>?
+
+    /**
+     * Returns the nonce for the smart account.
+     *
+     * @param key Optional key to retrieve the nonce for.
+     * @return The nonce of the smart account.
+     */
+    abstract suspend fun getNonce(key: BigInteger? = null): BigInteger
+
+    /**
+     * Returns the stub signature for the given user operation.
+     *
+     * @param userOp The user operation to retrieve the stub signature for. Type T must be the subclass of UserOperation.
+     * @return The stub signature.
+     */
+    abstract fun <T : UserOperation> getStubSignature(userOp: T): String
+
+    /**
+     * Signs the given hex data.
+     *
+     * @param context The context in which the signing operation is performed.
+     * @param hex The hex data to sign.
+     * @return The signed data.
+     */
+    abstract suspend fun sign(context: Context, hex: String): String
+
+    /**
+     * Signs the given message.
+     *
+     * @param context The context in which the signing operation is performed.
+     * @param message The message to sign.
+     * @return The signed message.
+     */
+    abstract suspend fun signMessage(context: Context, message: String): String
+
+    /**
+     * Signs the given typed data.
+     *
+     * @param context The context in which the signing operation is performed.
+     * @param typedData The typed data to sign.
+     * @return The signed typed data.
+     */
+    abstract suspend fun signTypedData(context: Context, typedData: String): String
+
+    /**
+     * Signs the given user operation.
+     *
+     * @param context The context in which the signing operation is performed.
+     * @param chainId The chain ID for the user operation. Default is the chain ID of the client.
+     * @param userOp The user operation to sign.
+     * @return The signed user operation.
+     */
+    abstract suspend fun signUserOperation(
+        context: Context,
+        chainId: Long = client.chain.chainId,
+        userOp: UserOperationV07
+    ): String
+
+    /**
+     * Retrieves the initialization code for the smart account.
+     *
+     * @return The initialization code.
+     */
+    abstract suspend fun getInitCode(): String?
+}
+
+data class UserOperationConfiguration @JvmOverloads constructor(var estimateGas: (suspend (UserOperation) -> EstimateUserOperationGasResult)? = null)
diff --git a/lib/src/main/java/com/circle/modularwallets/core/accounts/WebAuthnAccount.kt b/lib/src/main/java/com/circle/modularwallets/core/accounts/WebAuthnAccount.kt
new file mode 100644
index 0000000..ee80b1d
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/accounts/WebAuthnAccount.kt
@@ -0,0 +1,117 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.accounts
+
+import android.content.Context
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.models.AuthenticationCredential
+import com.circle.modularwallets.core.models.SignResult
+import com.circle.modularwallets.core.models.toWebAuthnData
+import com.circle.modularwallets.core.utils.fromJson
+import com.circle.modularwallets.core.utils.signature.adjustSignature
+import com.circle.modularwallets.core.utils.signature.hashMessage
+import com.circle.modularwallets.core.utils.signature.hashTypedData
+import com.circle.modularwallets.core.utils.signature.parseAsn1Signature
+import com.circle.modularwallets.core.utils.signature.serializeSignature
+import com.circle.modularwallets.core.utils.webauthn.getRequestOptions
+import com.circle.modularwallets.core.utils.webauthn.getSavedCredentials
+
+/**
+ * Creates a WebAuthn account.
+ *
+ * @param credential The WebAuthn credential associated with the account.
+ * @return The created WebAuthn account.
+ */
+fun toWebAuthnAccount(credential: WebAuthnCredential): WebAuthnAccount {
+    return WebAuthnAccount(credential)
+}
+
+/**
+ * Class representing a WebAuthn account.
+ *
+ * @param credential The WebAuthn credential associated with the account.
+ */
+open class WebAuthnAccount internal constructor(internal val credential: WebAuthnCredential) :
+    Account<SignResult>() {
+    /**
+     * Retrieves the address of the WebAuthn account.
+     *
+     * @return The public key associated with the WebAuthn credential.
+     */
+    override fun getAddress(): String {
+        return credential.publicKey
+    }
+
+    /**
+     * Signs the given hex data.
+     *
+     * @param context The context used to launch framework UI flows ; use an activity context to make sure the UI will be launched within the same task stack.
+     * @param hex The hex data to sign.
+     * @return The result of the signing operation.
+     * @throws BaseError if the credential request fails.
+     */
+    @ExcludeFromGeneratedCCReport
+    @Throws(Exception::class)
+    override suspend fun sign(context: Context, hex: String): SignResult {
+        val optionsAndJson = getRequestOptions(credential.rpId, credential.id, hex)
+        val authRespJson = getSavedCredentials(context, optionsAndJson.second)
+        val authResp = fromJson(authRespJson, AuthenticationCredential::class.java)
+            ?: throw BaseError("credential request failed. Get null from json\n${authRespJson}")
+        val ecdsaSigner = parseAsn1Signature(authResp.response.signature)
+        val (r, s) = adjustSignature(ecdsaSigner.r, ecdsaSigner.s)
+        val signatureHex = serializeSignature(r, s)
+        return SignResult(
+            signatureHex,
+            authResp.toWebAuthnData(optionsAndJson.first.userVerification),
+            authResp
+        )
+    }
+
+    /**
+     * Signs the given message.
+     *
+     * @param context The context used to launch framework UI flows ; use an activity context to make sure the UI will be launched within the same task stack.
+     * @param message The message to sign.
+     * @return The result of the signing operation.
+     * @throws BaseError if the credential request fails.
+     */
+    @ExcludeFromGeneratedCCReport
+    @Throws(Exception::class)
+    override suspend fun signMessage(context: Context, message: String): SignResult {
+        val hash = hashMessage(message.toByteArray())
+        return sign(context, hash)
+    }
+
+    /**
+     * Signs the given typed data.
+     *
+     * @param context The context used to launch framework UI flows ; use an activity context to make sure the UI will be launched within the same task stack.
+     * @param typedData The typed data to sign.
+     * @return The result of the signing operation.
+     * @throws BaseError if the credential request fails.
+     */
+    @ExcludeFromGeneratedCCReport
+    @Throws(Exception::class)
+    override suspend fun signTypedData(context: Context, typedData: String): SignResult {
+        val hash = hashTypedData(typedData)
+        return sign(context, hash)
+    }
+}
+
diff --git a/lib/src/main/java/com/circle/modularwallets/core/accounts/WebAuthnCredential.kt b/lib/src/main/java/com/circle/modularwallets/core/accounts/WebAuthnCredential.kt
new file mode 100644
index 0000000..9963c01
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/accounts/WebAuthnCredential.kt
@@ -0,0 +1,134 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.accounts
+
+import android.content.Context
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.circle.modularwallets.core.apis.rp.RpApiImpl
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.models.AuthenticationCredential
+import com.circle.modularwallets.core.models.PublicKeyCredential
+import com.circle.modularwallets.core.models.RegistrationCredential
+import com.circle.modularwallets.core.models.WebAuthnMode
+import com.circle.modularwallets.core.transports.Transport
+import com.circle.modularwallets.core.utils.fromJson
+import com.circle.modularwallets.core.utils.signature.parseCredentialPublicKey
+import com.circle.modularwallets.core.utils.signature.serializePublicKey
+import com.circle.modularwallets.core.utils.webauthn.createPasskey
+import com.circle.modularwallets.core.utils.webauthn.getSavedCredentials
+
+/**
+ * Logs in or registers a user and returns a WebAuthnCredential.
+ *
+ * @param context The context used to launch framework UI flows ; use an activity context to make sure the UI will be launched within the same task stack.
+ * @param transport The transport used to communicate with the RP API.
+ * @param userName  The username of the user. (required for WebAuthnMode.Register)
+ * @param mode The mode of the WebAuthn credential.
+ * @return The created WebAuthn credential.
+ * Throws: BaseError if userName is null for WebAuthnMode.Register.
+ *
+ */
+
+@ExcludeFromGeneratedCCReport
+@Throws(Exception::class)
+@JvmOverloads
+suspend fun toWebAuthnCredential(
+    context: Context,
+    transport: Transport,
+    userName: String? = null,
+    mode: WebAuthnMode
+): WebAuthnCredential {
+    return when (mode) {
+        WebAuthnMode.Register -> {
+            userName ?: throw BaseError("userName cannot be null")
+            WebAuthnCredential.register(context, transport, userName)
+        }
+
+        WebAuthnMode.Login -> WebAuthnCredential.login(context, transport)
+    }
+}
+
+/**
+ * Data class representing a P-256 WebAuthn Credential.
+ *
+ * @param id The unique identifier for the credential.
+ * @param publicKey The public key associated with the credential.
+ * @param raw Web Authentication API returned PublicKeyCredential object.
+ * @param rpId The relying party identifier.
+ */
+class WebAuthnCredential(
+    val id: String,
+    val publicKey: String,
+    val raw: PublicKeyCredential,
+    val rpId: String
+) {
+    companion object {
+        @ExcludeFromGeneratedCCReport
+        internal suspend fun register(
+            context: Context,
+            transport: Transport,
+            userName: String
+        ): WebAuthnCredential {
+            /** 1. RP getRegistrationOptions */
+            val rpApi =
+                RpApiImpl(transport)
+            val (options, optionsJson) = rpApi.getRegistrationOptions(userName)
+            /** 2. Create credential */
+            val registerRespJson = createPasskey(context, optionsJson).registrationResponseJson
+            val registerResp = fromJson(registerRespJson, RegistrationCredential::class.java)
+                ?: throw BaseError("credential request failed. RegistrationCredential is null\n${registerRespJson}")
+            /** 3. RP getRegistrationVerification */
+            rpApi.getRegistrationVerification(registerResp)
+            /** 4. Parse and serialized public key */
+            val publicKey = parseCredentialPublicKey(registerResp.response.publicKey)
+            val serializedPublicKey = serializePublicKey(publicKey)
+            return WebAuthnCredential(
+                registerResp.id,
+                serializedPublicKey,
+                registerResp,
+                options.rp.id
+            )
+        }
+
+        @ExcludeFromGeneratedCCReport
+        internal suspend fun login(
+            context: Context,
+            transport: Transport
+        ): WebAuthnCredential {
+            /** 1. RP getLoginOptions */
+            val rpApi =
+                RpApiImpl(transport)
+            val (options, optionsJson) = rpApi.getLoginOptions()
+
+            /** 2. Get credential */
+            val authRespJson = getSavedCredentials(context, optionsJson)
+            val authResp = fromJson(authRespJson, AuthenticationCredential::class.java)
+                ?: throw BaseError("credential request failed. AuthenticationCredential is null\n${authRespJson}")
+
+            /** 3. RP getLoginVerification */
+            val cPublicKey = rpApi.getLoginVerification(authResp)
+
+            /** 4. Parse and serialized public key */
+            val publicKey = parseCredentialPublicKey(cPublicKey)
+            val serializedPublicKey = serializePublicKey(publicKey)
+            return WebAuthnCredential(authResp.id, serializedPublicKey, authResp, options.rpId)
+        }
+    }
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/annotation/ExcludeFromGeneratedCCReport.kt b/lib/src/main/java/com/circle/modularwallets/core/annotation/ExcludeFromGeneratedCCReport.kt
new file mode 100644
index 0000000..dde00ae
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/annotation/ExcludeFromGeneratedCCReport.kt
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.annotation
+
+/**
+ * @suppress
+ */
+@MustBeDocumented
+@Retention(AnnotationRetention.RUNTIME)
+@Target(
+    AnnotationTarget.ANNOTATION_CLASS,
+    AnnotationTarget.CLASS,
+    AnnotationTarget.FIELD,
+    AnnotationTarget.FUNCTION,
+    AnnotationTarget.PROPERTY_GETTER,
+    AnnotationTarget.PROPERTY_SETTER,
+    AnnotationTarget.CONSTRUCTOR,
+    AnnotationTarget.LOCAL_VARIABLE, AnnotationTarget.PROPERTY
+)
+internal annotation class ExcludeFromGeneratedCCReport
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerApi.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerApi.kt
new file mode 100644
index 0000000..bd407e6
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerApi.kt
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.bundler
+
+import com.circle.modularwallets.core.accounts.SmartAccount
+import com.circle.modularwallets.core.clients.BundlerClient
+import com.circle.modularwallets.core.models.EncodeCallDataArg
+import com.circle.modularwallets.core.models.EntryPoint
+import com.circle.modularwallets.core.models.EstimateFeesPerGasResult
+import com.circle.modularwallets.core.models.EstimateUserOperationGasResult
+import com.circle.modularwallets.core.models.Paymaster
+import com.circle.modularwallets.core.models.UserOperation
+import com.circle.modularwallets.core.models.UserOperationRpc
+import com.circle.modularwallets.core.models.UserOperationV07
+import com.circle.modularwallets.core.transports.Transport
+
+internal interface BundlerApi {
+    suspend fun <T : UserOperation> estimateUserOperationGas(
+        transport: Transport,
+        userOp: T,
+        entryPoint: EntryPoint
+    ): EstimateUserOperationGasResult
+
+    suspend fun getChainId(transport: Transport): String
+    suspend fun getSupportedEntryPoints(transport: Transport): ArrayList<String>
+    suspend fun getUserOperation(transport: Transport, userOpHash: String): GetUserOperationResp
+    suspend fun getUserOperationReceipt(
+        transport: Transport,
+        userOpHash: String
+    ): UserOperationReceiptRpc
+
+    suspend fun prepareUserOperation(
+        transport: Transport,
+        account: SmartAccount,
+        calls: Array<EncodeCallDataArg>?,
+        partialUserOp: UserOperationV07,
+        paymaster: Paymaster?,
+        bundlerClient: BundlerClient,
+        estimateFeesPerGas: (suspend (SmartAccount, BundlerClient, UserOperationV07) -> EstimateFeesPerGasResult)?
+    ): UserOperationV07
+
+    suspend fun sendUserOperation(
+        transport: Transport,
+        userOpRpc: UserOperationRpc,
+        entryPointAddress: String,
+    ): String
+
+    suspend fun waitForUserOperationReceipt(
+        transport: Transport,
+        userOpHash: String,
+        pollingInterval: Long,
+        retryCount: Int,
+        timeout: Long? = null
+    ): UserOperationReceiptRpc
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerApiImpl.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerApiImpl.kt
new file mode 100644
index 0000000..c807deb
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerApiImpl.kt
@@ -0,0 +1,378 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.bundler
+
+import com.circle.modularwallets.core.accounts.SmartAccount
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.circle.modularwallets.core.apis.paymaster.PaymasterApiImpl
+import com.circle.modularwallets.core.apis.public.FeeValuesType
+import com.circle.modularwallets.core.apis.public.PublicApi
+import com.circle.modularwallets.core.apis.public.PublicApiImpl
+import com.circle.modularwallets.core.clients.BundlerClient
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.errors.BaseErrorParameters
+import com.circle.modularwallets.core.errors.UserOperationReceiptNotFoundError
+import com.circle.modularwallets.core.errors.WaitForUserOperationReceiptTimeoutError
+import com.circle.modularwallets.core.models.EncodeCallDataArg
+import com.circle.modularwallets.core.models.EntryPoint
+import com.circle.modularwallets.core.models.EstimateFeesPerGasResult
+import com.circle.modularwallets.core.models.EstimateUserOperationGasResult
+import com.circle.modularwallets.core.models.Paymaster
+import com.circle.modularwallets.core.models.UserOperation
+import com.circle.modularwallets.core.models.UserOperationRpc
+import com.circle.modularwallets.core.models.UserOperationV07
+import com.circle.modularwallets.core.models.toRpcUserOperation
+import com.circle.modularwallets.core.transports.RpcRequest
+import com.circle.modularwallets.core.transports.Transport
+import com.circle.modularwallets.core.utils.Logger
+import com.circle.modularwallets.core.utils.error.getUserOperationError
+import com.circle.modularwallets.core.utils.rpc.performJsonRpcRequest
+import com.circle.modularwallets.core.utils.unit.parseGwei
+import kotlinx.coroutines.TimeoutCancellationException
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.withTimeout
+import java.math.BigInteger
+
+internal object BundlerApiImpl : BundlerApi {
+    private val publicApi: PublicApi = PublicApiImpl
+    override suspend fun <T : UserOperation> estimateUserOperationGas(
+        transport: Transport,
+        userOp: T,
+        entryPoint: EntryPoint
+    ): EstimateUserOperationGasResult {
+        val userOpRpc =
+            if (userOp is UserOperationV07) userOp.toRpcUserOperation() else userOp.toRpcUserOperation()
+        try {
+            val req = RpcRequest(
+                "eth_estimateUserOperationGas",
+                listOf<Any>(userOpRpc, entryPoint.address)
+            )
+            val result =
+                performJsonRpcRequest(transport, req, EstimateUserOperationGasResp::class.java)
+            return result.first.toResult()
+        } catch (e: Throwable) {
+            if (e is BaseError) {
+                throw getUserOperationError(e, userOpRpc)
+            }
+            throw getUserOperationError(
+                BaseError(e.message ?: "", BaseErrorParameters(cause = e)),
+                userOpRpc
+            )
+        }
+    }
+
+    override suspend fun getChainId(transport: Transport): String {
+        return publicApi.getChainId(transport)
+    }
+
+    override suspend fun getSupportedEntryPoints(transport: Transport): ArrayList<String> {
+        val req = RpcRequest("eth_supportedEntryPoints")
+        val r = performJsonRpcRequest(transport, req)
+        return when (r) {
+            is String -> arrayListOf(r)
+            is List<*> -> r.filterIsInstance<String>().takeIf { it.isNotEmpty() }?.let(::ArrayList)
+            else -> null
+        } ?: throw BaseError("getSupportedEntryPoints failed while casting")
+    }
+
+    override suspend fun waitForUserOperationReceipt(
+        transport: Transport,
+        userOpHash: String,
+        pollingInterval: Long,
+        retryCount: Int,
+        timeout: Long?
+    ): UserOperationReceiptRpc {
+        try{
+            if (timeout != null) {
+                return withTimeout(timeout) {
+                    return@withTimeout startPolling(pollingInterval, retryCount) {
+                        try {
+                            return@startPolling getUserOperationReceipt(transport, userOpHash)
+                        } catch (e: UserOperationReceiptNotFoundError) {
+                            return@startPolling null
+                        }
+                    }
+                } ?: throw WaitForUserOperationReceiptTimeoutError(userOpHash)
+            } else {
+                return startPolling(pollingInterval, retryCount) {
+                    try {
+                        return@startPolling getUserOperationReceipt(transport, userOpHash)
+                    } catch (e: UserOperationReceiptNotFoundError) {
+                        return@startPolling null
+                    }
+                } ?: throw WaitForUserOperationReceiptTimeoutError(userOpHash)
+            }
+        } catch (e: TimeoutCancellationException){
+            throw WaitForUserOperationReceiptTimeoutError(userOpHash)
+        }
+    }
+
+    override suspend fun getUserOperation(
+        transport: Transport,
+        userOpHash: String
+    ): GetUserOperationResp {
+        val req = RpcRequest("eth_getUserOperationByHash", listOf<Any>(userOpHash))
+        val result = performJsonRpcRequest(
+            transport,
+            req,
+            GetUserOperationResp::class.java,
+            UserOperationReceiptNotFoundError(userOpHash)
+        )
+        return result.first
+    }
+
+    override suspend fun getUserOperationReceipt(
+        transport: Transport,
+        userOpHash: String
+    ): UserOperationReceiptRpc {
+        val req = RpcRequest("eth_getUserOperationReceipt", listOf<Any>(userOpHash))
+        val result = performJsonRpcRequest(
+            transport,
+            req,
+            UserOperationReceiptRpc::class.java,
+            UserOperationReceiptNotFoundError(userOpHash)
+        )
+        return result.first
+    }
+
+    override suspend fun prepareUserOperation(
+        transport: Transport,
+        account: SmartAccount,
+        calls: Array<EncodeCallDataArg>?,
+        partialUserOp: UserOperationV07,
+        paymaster: Paymaster?,
+        bundlerClient: BundlerClient,
+        estimateFeesPerGas: (suspend (SmartAccount, BundlerClient, UserOperationV07) -> EstimateFeesPerGasResult)?
+    ): UserOperationV07 {
+        account.userOperation?.estimateGas?.let {
+            val r = it.invoke(partialUserOp)
+            r.preVerificationGas?.let {
+                partialUserOp.preVerificationGas = it
+            }
+            r.verificationGasLimit?.let {
+                partialUserOp.verificationGasLimit = it
+            }
+            r.callGasLimit?.let {
+                partialUserOp.callGasLimit = it
+            }
+            r.paymasterVerificationGasLimit?.let {
+                partialUserOp.paymasterVerificationGasLimit = it
+            }
+            r.paymasterPostOpGasLimit?.let {
+                partialUserOp.paymasterPostOpGasLimit = it
+            }
+        }
+
+        val userOp = partialUserOp.copy()
+        userOp.sender = account.getAddress()
+
+        calls?.let {
+            val updatedCalls = getUpdatedCalls(it)
+            userOp.callData = account.encodeCalls(updatedCalls)
+        }
+
+        if (partialUserOp.factory.isNullOrBlank() or partialUserOp.factoryData.isNullOrBlank()) {
+            val arg = account.getFactoryArgs()
+            arg?.let {
+                userOp.factory = arg.first
+                userOp.factoryData = arg.second
+            }
+        }
+        try {
+            if (partialUserOp.maxFeePerGas == null || partialUserOp.maxPriorityFeePerGas == null) {
+                if (estimateFeesPerGas == null) {
+                    val defaultMaxFeePerGas = parseGwei("3")
+                    val defaultMaxPriorityFeePerGas = parseGwei("1")
+                    val two = BigInteger.valueOf(2)
+                    val fees = publicApi.estimateFeesPerGas(
+                        account.client.transport,
+                        FeeValuesType.eip1559
+                    )
+
+                    if (partialUserOp.maxFeePerGas == null) {
+                        userOp.maxFeePerGas = defaultMaxFeePerGas
+                        fees.maxFeePerGas?.let {
+                            userOp.maxFeePerGas = defaultMaxFeePerGas.max(it.multiply(two))
+                        }
+                    }
+                    if (partialUserOp.maxPriorityFeePerGas == null) {
+                        userOp.maxPriorityFeePerGas = defaultMaxPriorityFeePerGas
+                        fees.maxPriorityFeePerGas?.let {
+                            userOp.maxPriorityFeePerGas =
+                                defaultMaxPriorityFeePerGas.max(it.multiply(two))
+                        }
+                    }
+                } else {
+                    val r = estimateFeesPerGas(account, bundlerClient, userOp)
+                    if (partialUserOp.maxFeePerGas == null) {
+                        userOp.maxFeePerGas = r.maxFeePerGas
+                    }
+                    if (partialUserOp.maxPriorityFeePerGas == null) {
+                        userOp.maxPriorityFeePerGas = r.maxPriorityFeePerGas
+                    }
+                }
+            }
+        } catch (e: Throwable) {
+            e.printStackTrace()
+        }
+
+        if (partialUserOp.nonce == null) {
+            userOp.nonce = account.getNonce()
+        }
+        if (partialUserOp.signature.isNullOrBlank()) {
+            userOp.signature = account.getStubSignature(partialUserOp)
+        }
+        var isPaymasterPopulated = false
+        if (paymaster != null) {
+            val stubR = when (paymaster) {
+                is Paymaster.True -> {
+                    PaymasterApiImpl.getPaymasterStubData(
+                        transport,
+                        userOp,
+                        account.entryPoint,
+                        bundlerClient.chain.chainId,
+                        paymaster.paymasterContext
+                    )
+                }
+
+                is Paymaster.Client -> {
+                    PaymasterApiImpl.getPaymasterStubData(
+                        paymaster.client.transport,
+                        userOp,
+                        account.entryPoint,
+                        bundlerClient.chain.chainId,
+                        paymaster.paymasterContext
+                    )
+                }
+            }
+
+
+            isPaymasterPopulated = stubR.isFinal
+            userOp.paymaster = stubR.paymaster
+            userOp.paymasterVerificationGasLimit = stubR.paymasterVerificationGasLimit
+            userOp.paymasterPostOpGasLimit = stubR.paymasterPostOpGasLimit
+            userOp.paymasterData = stubR.paymasterData
+        }
+
+        // If not all the gas properties are already populated, we will need to estimate the gas
+        // to fill the gas properties.
+        if (userOp.preVerificationGas == null ||
+            userOp.verificationGasLimit == null ||
+            userOp.callGasLimit == null ||
+            (paymaster != null && userOp.paymasterVerificationGasLimit == null) ||
+            (paymaster != null && userOp.paymasterPostOpGasLimit == null)
+        ) {
+            // Some Bundlers fail if nullish gas values are provided for gas estimation :') –
+            // so we will need to set a default zeroish value.
+            val tmpUserOp = userOp.copy()
+            tmpUserOp.callGasLimit = BigInteger.ZERO
+            tmpUserOp.preVerificationGas = BigInteger.ZERO
+            if(paymaster != null){
+                tmpUserOp.paymasterVerificationGasLimit = BigInteger.ZERO
+                tmpUserOp.paymasterPostOpGasLimit = BigInteger.ZERO
+            } else{
+                tmpUserOp.paymasterVerificationGasLimit = null
+                tmpUserOp.paymasterPostOpGasLimit = null
+            }
+            val r = estimateUserOperationGas(transport, tmpUserOp, account.entryPoint)
+            userOp.callGasLimit =
+                if (userOp.callGasLimit == null) r.callGasLimit else userOp.callGasLimit
+            userOp.preVerificationGas =
+                if (userOp.preVerificationGas == null) r.preVerificationGas else userOp.preVerificationGas
+            userOp.verificationGasLimit =
+                if (userOp.verificationGasLimit == null) r.verificationGasLimit else userOp.verificationGasLimit
+            userOp.paymasterPostOpGasLimit =
+                if (userOp.paymasterPostOpGasLimit == null) r.paymasterPostOpGasLimit else userOp.paymasterPostOpGasLimit
+            userOp.paymasterVerificationGasLimit =
+                if (userOp.paymasterVerificationGasLimit == null) r.paymasterVerificationGasLimit else userOp.paymasterVerificationGasLimit
+        }
+        if (paymaster != null && !isPaymasterPopulated) {
+            val r = when (paymaster) {
+                is Paymaster.True -> {
+                    PaymasterApiImpl.getPaymasterData(
+                        transport,
+                        userOp,
+                        account.entryPoint,
+                        bundlerClient.chain.chainId,
+                        paymaster.paymasterContext
+                    )
+                }
+
+                is Paymaster.Client -> {
+                    PaymasterApiImpl.getPaymasterData(
+                        paymaster.client.transport,
+                        userOp,
+                        account.entryPoint,
+                        bundlerClient.chain.chainId,
+                        paymaster.paymasterContext
+                    )
+                }
+            }
+            userOp.paymaster = r.paymaster
+            userOp.paymasterData = r.paymasterData
+        }
+        return userOp
+    }
+
+    @ExcludeFromGeneratedCCReport
+    override suspend fun sendUserOperation(
+        transport: Transport,
+        userOpRpc: UserOperationRpc,
+        entryPointAddress: String,
+    ): String {
+        try {
+            val req = RpcRequest("eth_sendUserOperation", listOf(userOpRpc, entryPointAddress))
+            val result = performJsonRpcRequest(transport, req) as String
+            return result
+        } catch (e: Throwable) {
+            if (e is BaseError) {
+                throw getUserOperationError(e, userOpRpc)
+            }
+            throw getUserOperationError(
+                BaseError(e.message ?: "", BaseErrorParameters(cause = e)),
+                userOpRpc
+            )
+        }
+    }
+}
+internal fun getUpdatedCalls(calls: Array<EncodeCallDataArg>): Array<EncodeCallDataArg>{
+    val updatedCalls: Array<EncodeCallDataArg> = calls.map { call ->
+        return@map call.dataUpdated()
+    }.toTypedArray()
+    return updatedCalls
+}
+internal suspend fun <T> startPolling(
+    pollingInterval: Long,
+    retryCount: Int,
+    block: suspend () -> T
+): T? {
+    var currentCount = 0
+    while (currentCount < retryCount) {
+        Logger.i("startPolling", "Polling currentCount: $currentCount")
+        val result = block()
+        if (result != null) {
+            Logger.i("startPolling", "Polling got result: $currentCount")
+            return result
+        }
+        currentCount++
+        delay(pollingInterval)
+    }
+    Logger.i("startPolling", "Polling no result")
+    return null
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerReqResp.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerReqResp.kt
new file mode 100644
index 0000000..7be518d
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerReqResp.kt
@@ -0,0 +1,184 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.bundler
+
+import com.circle.modularwallets.core.models.EstimateUserOperationGasResult
+import com.circle.modularwallets.core.models.UserOperationReceipt
+import com.circle.modularwallets.core.models.GetUserOperationResult
+import com.circle.modularwallets.core.models.Log
+import com.circle.modularwallets.core.models.TransactionReceipt
+import com.circle.modularwallets.core.models.UserOperationRpc
+import com.circle.modularwallets.core.utils.encoding.hexToBigInteger
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+import java.math.BigInteger
+
+@JsonClass(generateAdapter = true)
+internal data class EstimateUserOperationGasResp(
+    @Json(name = "preVerificationGas") var preVerificationGasHex: String? = null,
+    @Json(name = "verificationGasLimit") var verificationGasLimitHex: String? = null,
+    @Json(name = "callGasLimit") var callGasLimitHex: String? = null,
+    @Json(name = "paymasterVerificationGasLimit") var paymasterVerificationGasLimitHex: String? = null,
+    @Json(name = "paymasterPostOpGasLimit") var paymasterPostOpGasLimitHex: String? = null,
+) {
+    val preVerificationGas: BigInteger?
+        get() = hexToBigInteger(preVerificationGasHex)
+    val verificationGasLimit: BigInteger?
+        get() = hexToBigInteger(verificationGasLimitHex)
+    val callGasLimit: BigInteger?
+        get() = hexToBigInteger(callGasLimitHex)
+    val paymasterVerificationGasLimit: BigInteger?
+        get() = hexToBigInteger(paymasterVerificationGasLimitHex)
+    val paymasterPostOpGasLimit: BigInteger?
+        get() = hexToBigInteger(paymasterPostOpGasLimitHex)
+}
+
+internal fun EstimateUserOperationGasResp.toResult(): EstimateUserOperationGasResult {
+    return EstimateUserOperationGasResult(
+        preVerificationGas = this.preVerificationGas,
+        verificationGasLimit = this.verificationGasLimit,
+        callGasLimit = this.callGasLimit,
+        paymasterVerificationGasLimit = this.paymasterVerificationGasLimit,
+        paymasterPostOpGasLimit = this.paymasterPostOpGasLimit,
+    )
+}
+
+internal data class UserOperationReceiptRpc(
+    val actualGasCost: String?,
+    val actualGasUsed: String?,
+    val entryPoint: String?,
+    val logs: List<LogRpc>?,
+    val nonce: String?,
+    val paymaster: String?,
+    val reason: String?,
+    val receipt: TransactionReceiptRpc,
+    val sender: String?,
+    val success: Boolean?,
+    val userOpHash: String?,
+)
+
+internal data class LogRpc(
+    val address: String?,
+    val blockHash: String?,
+    val blockNumber: String?,
+    val data: String?,
+    val logIndex: String?,
+    val transactionHash: String?,
+    val transactionIndex: String?,
+    val removed: Boolean?,
+    val topics: List<String>?,
+)
+
+internal data class TransactionReceiptRpc(
+    val blobGasPrice: String?,
+    val blobGasUsed: String?,
+    val blockHash: String?,
+    val blockNumber: String?,
+    val contractAddress: String?,
+    val cumulativeGasUsed: String?,
+    val effectiveGasPrice: String?,
+    val from: String?,
+    val gasUsed: String?,
+    val logs: List<LogRpc>?,
+    val logsBloom: String?,
+    val root: String?,
+    val status: String?,
+    val to: String?,
+    val transactionHash: String?,
+    val transactionIndex: String?,
+    val type: String?,
+)
+
+internal fun LogRpc.toLog(): Log {
+    return Log(
+        address = this.address,
+        blockHash = this.blockHash,
+        blockNumber = hexToBigInteger(this.blockNumber),
+        data = this.data,
+        logIndex = hexToBigInteger(this.logIndex),
+        transactionHash = this.transactionHash,
+        transactionIndex = hexToBigInteger(this.transactionIndex),
+        removed = this.removed,
+        topics = this.topics,
+    )
+}
+
+internal fun TransactionReceiptRpc.toTransactionReceipt(): TransactionReceipt {
+    return TransactionReceipt(
+        blobGasPrice = hexToBigInteger(this.blobGasPrice),
+        blobGasUsed = hexToBigInteger(this.blobGasUsed),
+        blockHash = this.blockHash,
+        blockNumber = hexToBigInteger(this.blockNumber),
+        contractAddress = this.contractAddress,
+        cumulativeGasUsed = hexToBigInteger(this.cumulativeGasUsed),
+        effectiveGasPrice = hexToBigInteger(this.effectiveGasPrice),
+        from = this.from,
+        gasUsed = hexToBigInteger(this.gasUsed),
+        logs = this.logs?.map { it.toLog() },
+        logsBloom = this.logsBloom,
+        root = this.root,
+        status = mapOf<String?, String>("0x0" to "reverted", "0x1" to "success")[this.status],
+        to = this.to,
+        transactionHash = this.transactionHash,
+        transactionIndex = hexToBigInteger(this.transactionIndex),
+        type = mapOf<String?, String>(
+            "0x0" to "legacy",
+            "0x1" to "eip2930",
+            "0x2" to "eip1559",
+            "0x3" to "eip4844",
+            "0x4" to "eip7702"
+        )[this.type],
+    )
+}
+
+internal fun UserOperationReceiptRpc.toUserOperationReceipt(): UserOperationReceipt {
+    return UserOperationReceipt(
+        actualGasCost = hexToBigInteger(this.actualGasCost),
+        actualGasUsed = hexToBigInteger(this.actualGasUsed),
+        entryPoint = this.entryPoint,
+        logs = this.logs?.map { it.toLog() },
+        nonce = hexToBigInteger(this.nonce),
+        paymaster = this.paymaster,
+        reason = this.reason,
+        receipt = this.receipt.toTransactionReceipt(),
+        sender = this.sender,
+        success = this.success,
+        userOpHash = this.userOpHash,
+    )
+}
+
+@JsonClass(generateAdapter = true)
+internal data class GetUserOperationResp(
+    @Json(name = "blockHash") val blockHash: String?,
+    @Json(name = "blockNumber") val blockNumber: String?,
+    @Json(name = "transactionHash") val transactionHash: String?,
+    @Json(name = "entryPoint") val entryPoint: String?,
+    @Json(name = "userOperation") val userOperation: UserOperationRpc?
+)
+
+internal fun GetUserOperationResp.toResult(): GetUserOperationResult {
+    return GetUserOperationResult(
+        blockHash = this.blockHash,
+        blockNumber = hexToBigInteger(this.blockNumber),
+        transactionHash = this.transactionHash,
+        entryPoint = this.entryPoint,
+        userOperation = this.userOperation
+    )
+
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/modular/ModularApi.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/modular/ModularApi.kt
new file mode 100644
index 0000000..2d78225
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/modular/ModularApi.kt
@@ -0,0 +1,26 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.modular
+
+import com.circle.modularwallets.core.transports.Transport
+
+internal interface ModularApi {
+    suspend fun getAddress(transport: Transport, getAddressReq: GetAddressReq): ModularWallet
+
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/modular/ModularApiImpl.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/modular/ModularApiImpl.kt
new file mode 100644
index 0000000..d1c7451
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/modular/ModularApiImpl.kt
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.modular
+
+import com.circle.modularwallets.core.transports.RpcRequest
+import com.circle.modularwallets.core.transports.Transport
+import com.circle.modularwallets.core.utils.rpc.performJsonRpcRequest
+
+internal object ModularApiImpl : ModularApi {
+    override suspend fun getAddress(
+        transport: Transport,
+        getAddressReq: GetAddressReq
+    ): ModularWallet {
+        val req = RpcRequest("circle_getAddress", listOf(getAddressReq))
+        val result = performJsonRpcRequest(transport, req, ModularWallet::class.java)
+        return result.first
+    }
+}
+
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/modular/ModularReqResp.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/modular/ModularReqResp.kt
new file mode 100644
index 0000000..e08d8e8
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/modular/ModularReqResp.kt
@@ -0,0 +1,120 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.apis.modular
+
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+
+/**
+ * Represents the Circle modular wallet.
+ *
+ * @property address The wallet address.
+ * @property blockchain The blockchain.
+ * @property state The state.
+ * @property name The name of the wallet.
+ * @property scaConfiguration The SCA configuratio.
+ */
+@JsonClass(generateAdapter = true)
+data class ModularWallet(
+    @Json(name = "address") val address: String,
+    @Json(name = "blockchain") val blockchain: String? = null,
+    @Json(name = "state") val state: String? = null,
+    @Json(name = "name") val name: String? = null,
+    @Json(name = "scaConfiguration") val scaConfiguration: ScaConfiguration,
+){
+    /**
+     * Gets the initialization code from the SCA configuration.
+     *
+     * @return The initialization code if present, null otherwise.
+     */
+    fun getInitCode(): String? {
+        return scaConfiguration.initCode
+    }
+}
+
+@JsonClass(generateAdapter = true)
+internal data class GetAddressReq(
+    @Json(name = "scaConfiguration") val scaConfiguration: ScaConfiguration,
+    @Json(name = "metadata") val matadata: Metadata,
+)
+
+@JsonClass(generateAdapter = true)
+data class ScaConfiguration(
+    @Json(name = "initialOwnershipConfiguration") val initialOwnershipConfiguration: InitialOwnershipConfiguration? = null,
+    @Json(name = "scaCore") val scaCore: String?, // req
+    @Json(name = "initCode") val initCode: String? = null, // resp
+)
+
+@JsonClass(generateAdapter = true)
+data class Metadata(
+    @Json(name = "name") val name: String? = null,
+)
+
+@JsonClass(generateAdapter = true)
+data class InitialOwnershipConfiguration(
+    @Json(name = "weightedMultisig") val weightedMultisig: WeightedMultiSig,
+    @Json(name = "ownershipContractAddress") val ownershipContractAddress: String? = null, // resp
+)
+
+@JsonClass(generateAdapter = true)
+data class WeightedMultiSig(
+    @Json(name = "webauthnOwners") val webauthnOwners: Array<WebauthnOwner>,
+    @Json(name = "thresholdWeight") val thresholdWeight: Int,
+    @Json(name = "owners") val owners: Array<EoaOwner>? = null,
+)
+
+@ExcludeFromGeneratedCCReport
+@JsonClass(generateAdapter = true)
+data class EoaOwner(
+    @Json(name = "address") val address: String,
+    @Json(name = "weight") val weight: Int,
+)
+
+@JsonClass(generateAdapter = true)
+data class WebauthnOwner(
+    @Json(name = "publicKeyX") val publicKeyX: String,
+    @Json(name = "publicKeyY") val publicKeyY: String,
+    @Json(name = "weight") val weight: Int,
+)
+
+
+internal fun getCreateWalletReq(
+    publicKeyX: String,
+    publicKeyY: String,
+    version: String,
+    name: String? = null
+): GetAddressReq {
+    return GetAddressReq(
+        ScaConfiguration(
+            InitialOwnershipConfiguration(
+                WeightedMultiSig(
+                    arrayOf(
+                        WebauthnOwner(
+                            publicKeyX, publicKeyY, 1
+                        )
+                    ), 1
+                )
+            ),
+            version
+        ),
+        Metadata(name)
+    )
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/paymaster/PaymasterApi.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/paymaster/PaymasterApi.kt
new file mode 100644
index 0000000..e8af1cc
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/paymaster/PaymasterApi.kt
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.paymaster
+
+import com.circle.modularwallets.core.models.EntryPoint
+import com.circle.modularwallets.core.models.IEntryPoint
+import com.circle.modularwallets.core.models.UserOperation
+import com.circle.modularwallets.core.transports.Transport
+
+internal interface PaymasterApi {
+    suspend fun <T : UserOperation> getPaymasterData(
+        transport: Transport,
+        userOp: T,
+        entryPoint: IEntryPoint,
+        chainId: Long,
+        context: Map<String, Any>?
+    ): GetPaymasterDataResp
+
+    suspend fun <T : UserOperation> getPaymasterStubData(
+        transport: Transport,
+        userOp: T,
+        entryPoint: IEntryPoint,
+        chainId: Long,
+        context: Map<String, Any>?
+    ): GetPaymasterStubDataResp
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/paymaster/PaymasterApiImpl.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/paymaster/PaymasterApiImpl.kt
new file mode 100644
index 0000000..56fa8e6
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/paymaster/PaymasterApiImpl.kt
@@ -0,0 +1,103 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.paymaster
+
+import com.circle.modularwallets.core.models.IEntryPoint
+import com.circle.modularwallets.core.models.UserOperation
+import com.circle.modularwallets.core.models.UserOperationV07
+import com.circle.modularwallets.core.models.toRpcUserOperation
+import com.circle.modularwallets.core.transports.RpcRequest
+import com.circle.modularwallets.core.transports.Transport
+import com.circle.modularwallets.core.utils.rpc.performJsonRpcRequest
+import okhttp3.internal.toHexString
+
+internal object PaymasterApiImpl : PaymasterApi {
+    override suspend fun <T : UserOperation> getPaymasterData(
+        transport: Transport,
+        userOp: T,
+        entryPoint: IEntryPoint,
+        chainId: Long,
+        context: Map<String, Any>?
+    ): GetPaymasterDataResp {
+        val rpcUserOp =
+            if (userOp is UserOperationV07) userOp.toRpcUserOperation() else userOp.toRpcUserOperation()
+        if (rpcUserOp.callGasLimit == null) {
+            rpcUserOp.callGasLimit = "0x0"
+        }
+        if (rpcUserOp.verificationGasLimit == null) {
+            rpcUserOp.verificationGasLimit = "0x0"
+        }
+        if (rpcUserOp.preVerificationGas == null) {
+            rpcUserOp.preVerificationGas = "0x0"
+        }
+        val param = if (context == null) listOf(
+            rpcUserOp,
+            entryPoint.address,
+            "0x${chainId.toHexString()}",
+        ) else listOf(
+            rpcUserOp,
+            entryPoint.address,
+            "0x${chainId.toHexString()}",
+            context
+        )
+        val jsonRpcReq = RpcRequest(
+            "pm_getPaymasterData",
+            param
+        )
+        val result = performJsonRpcRequest(transport, jsonRpcReq, GetPaymasterDataResp::class.java)
+        return result.first
+    }
+
+    override suspend fun <T : UserOperation> getPaymasterStubData(
+        transport: Transport,
+        userOp: T,
+        entryPoint: IEntryPoint,
+        chainId: Long,
+        context: Map<String, Any>?
+    ): GetPaymasterStubDataResp {
+        val rpcUserOp =
+            if (userOp is UserOperationV07) userOp.toRpcUserOperation() else userOp.toRpcUserOperation()
+        if (rpcUserOp.callGasLimit == null) {
+            rpcUserOp.callGasLimit = "0x0"
+        }
+        if (rpcUserOp.verificationGasLimit == null) {
+            rpcUserOp.verificationGasLimit = "0x0"
+        }
+        if (rpcUserOp.preVerificationGas == null) {
+            rpcUserOp.preVerificationGas = "0x0"
+        }
+
+        val param = if (context == null) listOf(
+            rpcUserOp,
+            entryPoint.address,
+            "0x${chainId.toHexString()}",
+        ) else listOf(
+            rpcUserOp,
+            entryPoint.address,
+            "0x${chainId.toHexString()}",
+            context
+        )
+        val jsonRpcReq = RpcRequest(
+            "pm_getPaymasterStubData", param
+        )
+        val result =
+            performJsonRpcRequest(transport, jsonRpcReq, GetPaymasterStubDataResp::class.java)
+        return result.first
+    }
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/paymaster/PaymasterReqResp.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/paymaster/PaymasterReqResp.kt
new file mode 100644
index 0000000..5847464
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/paymaster/PaymasterReqResp.kt
@@ -0,0 +1,82 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.paymaster
+
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.circle.modularwallets.core.models.GetPaymasterDataResult
+import com.circle.modularwallets.core.models.GetPaymasterStubDataResult
+import com.circle.modularwallets.core.models.Sponsor
+import com.circle.modularwallets.core.utils.encoding.hexToBigInteger
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+import java.math.BigInteger
+
+@ExcludeFromGeneratedCCReport
+@JsonClass(generateAdapter = true)
+internal data class GetPaymasterDataResp(
+    @Json(name = "paymasterAndData") var paymasterAndData: String? = null,
+    @Json(name = "paymasterData") var paymasterData: String? = null,
+    @Json(name = "paymaster") var paymaster: String? = null,
+    @Json(name = "paymasterPostOpGasLimit") var paymasterPostOpGasLimitHex: String? = null,
+    @Json(name = "paymasterVerificationGasLimit") var paymasterVerificationGasLimitHex: String? = null,
+) {
+    val paymasterPostOpGasLimit: BigInteger?
+        get() = hexToBigInteger(paymasterPostOpGasLimitHex)
+    val paymasterVerificationGasLimit: BigInteger?
+        get() = hexToBigInteger(paymasterVerificationGasLimitHex)
+}
+
+internal fun GetPaymasterDataResp.toResult(): GetPaymasterDataResult {
+    return GetPaymasterDataResult(
+        paymasterAndData = this.paymasterAndData,
+        paymaster = this.paymaster,
+        paymasterData = this.paymasterData,
+        paymasterPostOpGasLimit = this.paymasterPostOpGasLimit,
+        paymasterVerificationGasLimit = this.paymasterVerificationGasLimit,
+    )
+}
+
+@ExcludeFromGeneratedCCReport
+@JsonClass(generateAdapter = true)
+internal class GetPaymasterStubDataResp(
+    @Json(name = "paymasterAndData") var paymasterAndData: String? = null,
+    @Json(name = "paymaster") var paymaster: String? = null,
+    @Json(name = "paymasterData") var paymasterData: String? = null,
+    @Json(name = "paymasterPostOpGasLimit") var paymasterPostOpGasLimitHex: String? = null,
+    @Json(name = "paymasterVerificationGasLimit") var paymasterVerificationGasLimitHex: String? = null,
+    @Json(name = "isFinal") var isFinal: Boolean = false,
+    @Json(name = "sponsor") var sponsor: Sponsor? = null,
+) {
+    val paymasterPostOpGasLimit: BigInteger?
+        get() = hexToBigInteger(paymasterPostOpGasLimitHex)
+    val paymasterVerificationGasLimit: BigInteger?
+        get() = hexToBigInteger(paymasterVerificationGasLimitHex)
+}
+
+internal fun GetPaymasterStubDataResp.toResult(): GetPaymasterStubDataResult {
+    return GetPaymasterStubDataResult(
+        paymasterAndData = this.paymasterAndData,
+        paymaster = this.paymaster,
+        paymasterData = this.paymasterData,
+        paymasterPostOpGasLimit = this.paymasterPostOpGasLimit,
+        paymasterVerificationGasLimit = this.paymasterVerificationGasLimit,
+        isFinal = this.isFinal,
+        sponsor = this.sponsor,
+    )
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/public/BlockRpc.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/public/BlockRpc.kt
new file mode 100644
index 0000000..d4a1a88
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/public/BlockRpc.kt
@@ -0,0 +1,88 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.public
+
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.circle.modularwallets.core.models.Block
+import com.circle.modularwallets.core.models.Withdrawal
+import com.circle.modularwallets.core.utils.encoding.hexToBigInteger
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+
+@ExcludeFromGeneratedCCReport
+@JsonClass(generateAdapter = true)
+internal data class BlockRpc(
+    @Json(name = "baseFeePerGas") var baseFeePerGas: String? = null,
+    @Json(name = "blobGasUsed") var blobGasUsed: String? = null,
+    @Json(name = "difficulty") var difficulty: String? = null,
+    @Json(name = "excessBlobGas") var excessBlobGas: String? = null,
+    @Json(name = "extraData") var extraData: String? = null,
+    @Json(name = "gasLimit") var gasLimit: String? = null,
+    @Json(name = "gasUsed") var gasUsed: String? = null,
+    @Json(name = "hash") var hash: String? = null,
+    @Json(name = "logsBloom") var logsBloom: String? = null,
+    @Json(name = "miner") var miner: String? = null,
+    @Json(name = "mixHash") var mixHash: String? = null,
+    @Json(name = "nonce") var nonce: String? = null,
+    @Json(name = "number") var number: String? = null,
+    @Json(name = "parentBeaconBlockRoot") var parentBeaconBlockRoot: String? = null,
+    @Json(name = "parentHash") var parentHash: String? = null,
+    @Json(name = "receiptsRoot") var receiptsRoot: String? = null,
+    @Json(name = "sha3Uncles") var sha3Uncles: String? = null,
+    @Json(name = "size") var size: String? = null,
+    @Json(name = "stateRoot") var stateRoot: String? = null,
+    @Json(name = "timestamp") var timestamp: String? = null,
+    @Json(name = "totalDifficulty") var totalDifficulty: String? = null,
+    @Json(name = "transactions") var transactions: Array<String>? = null,
+    @Json(name = "transactionsRoot") var transactionsRoot: String? = null,
+    @Json(name = "uncles") var uncles: Array<String>? = null,
+    @Json(name = "withdrawals") var withdrawals: Array<Withdrawal>? = null,
+    @Json(name = "withdrawalsRoot") var withdrawalsRoot: String? = null,
+)
+
+internal fun BlockRpc.toBlock(): Block {
+    return Block(
+        baseFeePerGas = hexToBigInteger(this.baseFeePerGas),
+        blobGasUsed = hexToBigInteger(this.blobGasUsed),
+        difficulty = hexToBigInteger(this.difficulty),
+        excessBlobGas = hexToBigInteger(this.excessBlobGas),
+        extraData = this.extraData,
+        gasLimit = hexToBigInteger(this.gasLimit),
+        gasUsed = hexToBigInteger(this.gasUsed),
+        hash = this.hash,
+        logsBloom = this.logsBloom,
+        miner = this.miner,
+        mixHash = this.mixHash,
+        nonce = this.nonce,
+        number = hexToBigInteger(this.number),
+        parentBeaconBlockRoot = this.parentBeaconBlockRoot,
+        parentHash = this.parentHash,
+        receiptsRoot = this.receiptsRoot,
+        sha3Uncles = this.sha3Uncles,
+        size = hexToBigInteger(this.size),
+        stateRoot = this.stateRoot,
+        timestamp = hexToBigInteger(this.timestamp),
+        totalDifficulty = hexToBigInteger(this.totalDifficulty),
+        transactions = this.transactions,
+        transactionsRoot = this.transactionsRoot,
+        uncles = this.uncles,
+        withdrawals = this.withdrawals,
+        withdrawalsRoot = this.withdrawalsRoot,
+    )
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/public/PublicApi.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/public/PublicApi.kt
new file mode 100644
index 0000000..7104fb8
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/public/PublicApi.kt
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.public
+
+import com.circle.modularwallets.core.models.Block
+import com.circle.modularwallets.core.models.EstimateFeesPerGasResult
+import com.circle.modularwallets.core.transports.Transport
+import java.math.BigInteger
+
+interface PublicApi {
+    /** Returns the number of the most recent block seen. */
+    suspend fun getBlockNum(transport: Transport): BigInteger
+
+    /** Returns information about a block at a block number (hex) or tag. */
+    suspend fun getBlock(
+        transport: Transport,
+        includeTransactions: Boolean = false,
+        blockNumber: BigInteger
+    ): Block
+
+    /** Returns information about a block at a block number (hex) or tag. */
+    suspend fun getBlock(
+        transport: Transport,
+        includeTransactions: Boolean = false,
+        blockNumberHexOrTag: String = "latest"
+    ): Block
+
+    /** Returns the chain ID associated with the current network. */
+    suspend fun getChainId(transport: Transport): String
+
+    /** Executes a new message call immediately without submitting a transaction to the network. */
+    suspend fun call(transport: Transport, from: String?, to: String, data: String): String
+
+    /**
+     * The type of fee values to return.
+     * - `legacy`: Returns the legacy gas price.
+     * - `eip1559`: Returns the max fee per gas and max priority fee per gas.
+     * */
+    suspend fun estimateFeesPerGas(
+        transport: Transport,
+        type: FeeValuesType = FeeValuesType.eip1559
+    ): EstimateFeesPerGasResult
+
+    /** Returns the current price of gas (in wei) */
+    suspend fun getGasPrice(
+        transport: Transport,
+    ): BigInteger
+    /**  Retrieves the bytecode at an address. */
+    suspend fun getCode(transport: Transport, address: String, blockNumber: BigInteger): String
+    /**  Retrieves the bytecode at an address. */
+    suspend fun getCode(transport: Transport, address: String, blockNumberHexOrTag: String = "latest"): String
+    /** Returns the balance of an address in wei. */
+    suspend fun getBalance(transport: Transport, address: String, blockNumber: BigInteger): BigInteger
+    /** Returns the balance of an address in wei. */
+    suspend fun getBalance(transport: Transport, address: String, blockNumberHexOrTag: String = "latest"): BigInteger
+}
+
+enum class FeeValuesType {
+    legacy,
+    eip1559
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/public/PublicApiImpl.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/public/PublicApiImpl.kt
new file mode 100644
index 0000000..a89dc21
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/public/PublicApiImpl.kt
@@ -0,0 +1,187 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.public
+
+import com.circle.modularwallets.core.apis.util.UtilApiImpl
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.models.Block
+import com.circle.modularwallets.core.models.EstimateFeesPerGasResult
+import com.circle.modularwallets.core.transports.RpcRequest
+import com.circle.modularwallets.core.transports.Transport
+import com.circle.modularwallets.core.utils.encoding.bigIntegerToHex
+import com.circle.modularwallets.core.utils.encoding.hexToBigInteger
+import com.circle.modularwallets.core.utils.rpc.performJsonRpcRequest
+import org.web3j.protocol.core.methods.request.Transaction
+import java.math.BigInteger
+import kotlin.math.ceil
+import kotlin.math.pow
+
+internal object PublicApiImpl : PublicApi {
+
+    override suspend fun getChainId(transport: Transport): String {
+        val req = RpcRequest("eth_chainId")
+        val result: String = performJsonRpcRequest(transport, req) as String
+        return result
+    }
+
+    override suspend fun call(
+        transport: Transport,
+        from: String?,
+        to: String,
+        data: String
+    ): String {
+        val transaction = Transaction.createEthCallTransaction(from, to, data)
+        val req = RpcRequest("eth_call", listOf<Any>(transaction, "latest"))
+        val result: String = performJsonRpcRequest(transport, req) as String
+        return result
+    }
+
+    override suspend fun estimateFeesPerGas(
+        transport: Transport,
+        type: FeeValuesType
+    ): EstimateFeesPerGasResult {
+        val baseFeeMultiplier = 1.2
+        val block = getBlock(transport)
+        if (type == FeeValuesType.eip1559) {
+            block.baseFeePerGas?.let {
+                val maxPriorityFeePerGas = estimateMaxPriorityFeePerGas(transport, block)
+                val baseFeePerGas = multiply(it, baseFeeMultiplier)
+                val maxFeePerGas = baseFeePerGas + maxPriorityFeePerGas
+                return EstimateFeesPerGasResult(maxFeePerGas, maxPriorityFeePerGas)
+            }
+            throw BaseError("Eip1559FeesNotSupportedError")
+        }
+        return EstimateFeesPerGasResult(gasPrice = getGasPrice(transport))
+    }
+
+    override suspend fun getBalance(
+        transport: Transport,
+        address: String,
+        blockNumber: BigInteger
+    ): BigInteger {
+        val hex = bigIntegerToHex(blockNumber)
+        hex?.let {
+            return getBalance(transport, address, hex)
+        }
+        return getBalance(transport, address)
+    }
+
+    override suspend fun getBalance(
+        transport: Transport,
+        address: String,
+        blockNumberHexOrTag: String
+    ): BigInteger {
+        val req = RpcRequest("eth_getBalance", listOf<Any>(address, blockNumberHexOrTag))
+        val result: String = performJsonRpcRequest(transport, req) as String
+        return hexToBigInteger(result) ?: throw BaseError("Failed to transform to BigInteger")
+    }
+
+    override suspend fun getBlockNum(transport: Transport): BigInteger {
+        val req = RpcRequest("eth_blockNumber")
+        val result: String = performJsonRpcRequest(transport, req) as String
+        return hexToBigInteger(result) ?: throw BaseError("Failed to transform to BigInteger")
+    }
+
+    override suspend fun getBlock(
+        transport: Transport,
+        includeTransactions: Boolean,
+        blockNumber: BigInteger
+    ): Block {
+        val hex = bigIntegerToHex(blockNumber)
+        hex?.let {
+            return getBlock(transport, includeTransactions, hex)
+        }
+        return getBlock(transport, includeTransactions)
+    }
+
+    override suspend fun getBlock(
+        transport: Transport,
+        includeTransactions: Boolean,
+        blockNumberHexOrTag: String
+    ): Block {
+        val req = RpcRequest(
+            "eth_getBlockByNumber",
+            listOf<Any>(blockNumberHexOrTag, includeTransactions)
+        )
+        val result = performJsonRpcRequest(transport, req, BlockRpc::class.java)
+        return result.first.toBlock()
+    }
+
+    override suspend fun getGasPrice(
+        transport: Transport,
+    ): BigInteger {
+        val req = RpcRequest("eth_gasPrice")
+        val result: String = performJsonRpcRequest(transport, req) as String
+        return hexToBigInteger(result) ?: throw BaseError("Failed to transform to BigInteger")
+    }
+
+    override suspend fun getCode(
+        transport: Transport,
+        address: String,
+        blockNumber: BigInteger
+    ): String {
+        val hex = bigIntegerToHex(blockNumber)
+        hex?.let {
+            return getCode(transport, address, hex)
+        }
+        return getCode(transport, address)
+    }
+
+    override suspend fun getCode(
+        transport: Transport,
+        address: String,
+        blockNumberHexOrTag: String
+    ): String {
+        val req = RpcRequest("eth_getCode", listOf(address, blockNumberHexOrTag))
+        val result: String = performJsonRpcRequest(transport, req) as String
+        return result
+
+    }
+
+    private fun multiply(base: BigInteger, baseFeeMultiplier: Double): BigInteger {
+        val decimals = baseFeeMultiplier.toString().split(".").getOrNull(1)?.length ?: 0
+        val denominator = 10.0.pow(decimals).toLong()
+        val scaledMultiplier = ceil(baseFeeMultiplier * denominator).toLong()
+        return (base * BigInteger.valueOf(scaledMultiplier)) / BigInteger.valueOf(denominator)
+    }
+
+    private suspend fun estimateMaxPriorityFeePerGas(
+        transport: Transport,
+        block: Block
+    ): BigInteger {
+        return try {
+            UtilApiImpl.getMaxPriorityFeePerGas(transport)
+        } catch (e: Throwable) {
+            estimateMaxPriorityFeePerGasFallback(transport, block)
+        }
+    }
+
+    internal suspend fun estimateMaxPriorityFeePerGasFallback(
+        transport: Transport,
+        block: Block
+    ): BigInteger {
+        block.baseFeePerGas?.let {
+            val gasPrice = getGasPrice(transport)
+            val maxPriorityFeePerGas = gasPrice - it
+            return maxPriorityFeePerGas.max(BigInteger.ZERO)
+        }
+        throw BaseError("Eip1559FeesNotSupportedError")
+    }
+}
+
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/rp/PublicKeyCredentialOptions.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/rp/PublicKeyCredentialOptions.kt
new file mode 100644
index 0000000..fdf4761
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/rp/PublicKeyCredentialOptions.kt
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.apis.rp
+
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+
+// PublicKeyCredentialCreationOptions
+@ExcludeFromGeneratedCCReport
+@JsonClass(generateAdapter = true)
+internal data class PublicKeyCredentialCreationOptions(
+    @Json(name = "challenge") val challenge: String,
+    @Json(name = "rp") val rp: PublicKeyCredentialRpEntity,
+    @Json(name = "pubKeyCredParams") val pubKeyCredParams: List<PublicKeyCredentialParameters> = listOf(
+        PublicKeyCredentialParameters(-7, "public-key"),
+        PublicKeyCredentialParameters(-257, "public-key"),
+    ),
+    @Json(name = "authenticatorSelection") val authenticatorSelection: AuthenticatorSelectionCriteria = AuthenticatorSelectionCriteria(
+        residentKey = "required"
+    ),
+    @Json(name = "user") var user: PublicKeyCredentialUserEntity,
+    @Json(name = "timeout") val timeout: Long? = null,
+    @Json(name = "excludeCredentials") val excludeCredentials: MutableList<PublicKeyCredentialDescriptor>? = null,
+    @Json(name = "attestation") val attestation: String? = null,
+    @Json(name = "extensions") val extensions: String? = null,
+)
+@ExcludeFromGeneratedCCReport
+@JsonClass(generateAdapter = true)
+internal data class AuthenticatorSelectionCriteria(
+    @Json(name = "authenticatorAttachment") val authenticatorAttachment: String? = null,
+    @Json(name = "residentKey") val residentKey: String? = null,
+    @Json(name = "requireResidentKey") val requireResidentKey: Boolean? = null,
+    @Json(name = "userVerification") val userVerification: String? = null,
+)
+@ExcludeFromGeneratedCCReport
+@JsonClass(generateAdapter = true)
+internal data class PublicKeyCredentialRpEntity(
+    @Json(name = "id") var id: String,
+    @Json(name = "name") val name: String = "",
+)
+@ExcludeFromGeneratedCCReport
+@JsonClass(generateAdapter = true)
+internal data class PublicKeyCredentialParameters(
+    @Json(name = "alg") val alg: Int,
+    @Json(name = "type") val type: String,
+)
+@ExcludeFromGeneratedCCReport
+@JsonClass(generateAdapter = true)
+internal data class PublicKeyCredentialUserEntity(
+    @Json(name = "id") val id: String,
+    @Json(name = "name") val name: String,
+    @Json(name = "displayName") val displayName: String,
+)
+
+// PublicKeyCredentialRequestOptions
+@ExcludeFromGeneratedCCReport
+@JsonClass(generateAdapter = true)
+internal data class PublicKeyCredentialRequestOptions(
+    @Json(name = "challenge") val challenge: String,
+    @Json(name = "rpId") var rpId: String,
+    @Json(name = "allowCredentials") var allowCredentials: MutableList<PublicKeyCredentialDescriptor>? = null,
+    @Json(name = "timeout") val timeout: Long = 1800000,
+    @Json(name = "userVerification") val userVerification: String = "required",
+)
+@ExcludeFromGeneratedCCReport
+@JsonClass(generateAdapter = true)
+internal data class PublicKeyCredentialDescriptor(
+    @Json(name = "id") val id: String,
+    @Json(name = "transports") val transports: List<String>? = null,
+    @Json(name = "type") val type: String = "public-key",
+)
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/rp/RpApi.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/rp/RpApi.kt
new file mode 100644
index 0000000..6d35ca1
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/rp/RpApi.kt
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+
+package com.circle.modularwallets.core.apis.rp
+
+import com.circle.modularwallets.core.models.AuthenticationCredential
+import com.circle.modularwallets.core.models.RegistrationCredential
+
+internal interface RpApi {
+    suspend fun getRegistrationOptions(userName: String): Pair<PublicKeyCredentialCreationOptions, String>
+    suspend fun getRegistrationVerification(registrationCredential: RegistrationCredential): Boolean
+    suspend fun getLoginOptions(): Pair<PublicKeyCredentialRequestOptions, String>
+    suspend fun getLoginVerification(authenticationCredential: AuthenticationCredential): String
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/rp/RpApiImpl.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/rp/RpApiImpl.kt
new file mode 100644
index 0000000..5700b54
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/rp/RpApiImpl.kt
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.apis.rp
+
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.circle.modularwallets.core.models.AuthenticationCredential
+import com.circle.modularwallets.core.models.RegistrationCredential
+import com.circle.modularwallets.core.transports.RpcRequest
+import com.circle.modularwallets.core.transports.Transport
+import com.circle.modularwallets.core.utils.rpc.performJsonRpcRequest
+import com.circle.modularwallets.core.utils.toJson
+
+internal class RpApiImpl(val transport: Transport) : RpApi {
+    override suspend fun getRegistrationOptions(userName: String): Pair<PublicKeyCredentialCreationOptions, String> {
+        val req = RpcRequest("rp_getRegistrationOptions", listOf<Any>(userName))
+        val result =
+            performJsonRpcRequest(transport, req, PublicKeyCredentialCreationOptions::class.java)
+        return Pair(
+            result.first,
+            toJson(result.first)
+        )
+    }
+
+    @ExcludeFromGeneratedCCReport
+    override suspend fun getRegistrationVerification(registrationCredential: RegistrationCredential): Boolean {
+        val req = RpcRequest(
+            "rp_getRegistrationVerification",
+            listOf<Any>(registrationCredential)
+        )
+        return performJsonRpcRequest(transport, req) as Boolean
+    }
+
+    override suspend fun getLoginOptions(): Pair<PublicKeyCredentialRequestOptions, String> {
+        val req = RpcRequest("rp_getLoginOptions")
+        val result =
+            performJsonRpcRequest(transport, req, PublicKeyCredentialRequestOptions::class.java)
+        return Pair(
+            result.first,
+            toJson(result.first)
+        )
+    }
+
+    @ExcludeFromGeneratedCCReport
+    override suspend fun getLoginVerification(authenticationCredential: AuthenticationCredential): String {
+        val req =
+            RpcRequest("rp_getLoginVerification", listOf(authenticationCredential))
+        val result = performJsonRpcRequest(transport, req, GetLoginVerificationResp::class.java)
+        return result.first.publicKey
+    }
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/rp/RpReqResp.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/rp/RpReqResp.kt
new file mode 100644
index 0000000..d0e3275
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/rp/RpReqResp.kt
@@ -0,0 +1,29 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.rp
+
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+
+@ExcludeFromGeneratedCCReport
+@JsonClass(generateAdapter = true)
+internal data class GetLoginVerificationResp(
+    @Json(name = "publicKey") val publicKey: String,
+)
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/util/UtilApi.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/util/UtilApi.kt
new file mode 100644
index 0000000..256c9d3
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/util/UtilApi.kt
@@ -0,0 +1,61 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.util
+
+import com.circle.modularwallets.core.constants.CIRCLE_WEIGHTED_WEB_AUTHN_MULTISIG_PLUGIN
+import com.circle.modularwallets.core.transports.Transport
+import java.math.BigInteger
+
+internal interface UtilApi {
+    suspend fun getAddress(
+        transport: Transport,
+        to: String,
+        sender: ByteArray,
+        salt: ByteArray,
+        initializingData: ByteArray,
+    ): Pair<String, String>
+
+    suspend fun createAccount(
+        transport: Transport,
+        to: String,
+        sender: String,
+        salt: ByteArray,
+        initializingData: ByteArray,
+    ): String
+
+    suspend fun getNonce(
+        transport: Transport,
+        address: String,
+        to: String,
+        key: BigInteger = BigInteger.ZERO
+    ): BigInteger
+
+    suspend fun getMaxPriorityFeePerGas(
+        transport: Transport,
+    ): BigInteger
+
+    suspend fun isValidSignature(
+        transport: Transport,
+        message: String,
+        signature: String,
+        from: String,
+        to: String = CIRCLE_WEIGHTED_WEB_AUTHN_MULTISIG_PLUGIN.address
+    ): Boolean
+
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/util/UtilApiImpl.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/util/UtilApiImpl.kt
new file mode 100644
index 0000000..708f39a
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/util/UtilApiImpl.kt
@@ -0,0 +1,138 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.apis.util
+
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.circle.modularwallets.core.apis.public.PublicApiImpl.call
+import com.circle.modularwallets.core.constants.EIP1271_VALID_SIGNATURE
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.transports.RpcRequest
+import com.circle.modularwallets.core.transports.Transport
+import com.circle.modularwallets.core.utils.Logger
+import com.circle.modularwallets.core.utils.encoding.hexToBigInteger
+import com.circle.modularwallets.core.utils.encoding.toSha3Bytes
+import com.circle.modularwallets.core.utils.rpc.performJsonRpcRequest
+import org.web3j.abi.FunctionEncoder
+import org.web3j.abi.FunctionReturnDecoder
+import org.web3j.abi.TypeReference
+import org.web3j.abi.datatypes.Address
+import org.web3j.abi.datatypes.DynamicBytes
+import org.web3j.abi.datatypes.Function
+import org.web3j.abi.datatypes.Type
+import org.web3j.abi.datatypes.generated.Bytes32
+import org.web3j.abi.datatypes.generated.Bytes4
+import org.web3j.abi.datatypes.generated.Uint192
+import org.web3j.abi.datatypes.generated.Uint256
+import org.web3j.utils.Numeric
+import java.math.BigInteger
+
+internal object UtilApiImpl : UtilApi {
+    override suspend fun getAddress(
+        transport: Transport,
+        to: String,
+        sender: ByteArray,
+        salt: ByteArray,
+        initializingData: ByteArray,
+    ): Pair<String, String> {
+        val function = Function(
+            "getAddress",
+            listOf<Type<*>>(Bytes32(sender), Bytes32(salt), DynamicBytes(initializingData)),
+            listOf<TypeReference<*>>(
+                object : TypeReference<Address>() {},
+                object : TypeReference<Bytes32>() {})
+        )
+        val data = FunctionEncoder.encode(function)
+        Logger.d(msg = "getAddress > call")
+        val resp = call(transport, null, to, data)
+        val decoded = FunctionReturnDecoder.decode(resp, function.outputParameters)
+        return Pair(decoded[0].value as String, Numeric.toHexString(decoded[1].value as ByteArray))
+    }
+
+    override suspend fun createAccount(
+        transport: Transport,
+        to: String,
+        sender: String,
+        salt: ByteArray,
+        initializingData: ByteArray,
+    ): String {
+        val function = Function(
+            "createAccount",
+            listOf<Type<*>>(
+                Bytes32(Numeric.hexStringToByteArray(sender)),
+                Bytes32(salt),
+                DynamicBytes(initializingData)
+            ),
+            listOf<TypeReference<*>>(
+                object : TypeReference<Address>() {})
+        )
+        val data = FunctionEncoder.encode(function)
+        Logger.d(msg = "createAccount > call")
+        val resp = call(transport, null, to, data)
+        val decoded = FunctionReturnDecoder.decode(resp, function.outputParameters)
+        return decoded[0].value as String
+    }
+
+    override suspend fun getNonce(
+        transport: Transport,
+        address: String,
+        to: String,
+        key: BigInteger
+    ): BigInteger {
+        val function = Function(
+            "getNonce",
+            listOf<Type<*>>(Address(address), Uint192(key)),
+            listOf<TypeReference<*>>(object : TypeReference<Uint256>() {})
+        )
+        val data = FunctionEncoder.encode(function)
+        Logger.d(msg = "getNonce > call")
+        val resp = call(transport, null, to, data)
+        return hexToBigInteger(resp) ?: throw BaseError("Failed to transform to BigInteger")
+    }
+
+    override suspend fun getMaxPriorityFeePerGas(
+        transport: Transport,
+    ): BigInteger {
+        val req = RpcRequest("eth_maxPriorityFeePerGas")
+        val result: String = performJsonRpcRequest(transport, req) as String
+        return hexToBigInteger(result) ?: throw BaseError("Failed to transform to BigInteger")
+    }
+
+    @ExcludeFromGeneratedCCReport
+    override suspend fun isValidSignature(
+        transport: Transport,
+        message: String,
+        signature: String,
+        from: String,
+        to: String
+    ): Boolean {
+        val digest = toSha3Bytes(message)
+        val function = Function(
+            "isValidSignature",
+            listOf<Type<*>>(Bytes32(digest), DynamicBytes(Numeric.hexStringToByteArray(signature))),
+            listOf<TypeReference<*>>(
+                object : TypeReference<Bytes4>() {})
+        )
+        val data = FunctionEncoder.encode(function)
+        Logger.d(msg = "isValidSignature > call")
+        val resp = call(transport, from, to, data)
+        val decoded = FunctionReturnDecoder.decode(resp, function.outputParameters)
+        return EIP1271_VALID_SIGNATURE.contentEquals(decoded[0].value as ByteArray)
+    }
+}
+
diff --git a/lib/src/main/java/com/circle/modularwallets/core/chains/Arbitrum.kt b/lib/src/main/java/com/circle/modularwallets/core/chains/Arbitrum.kt
new file mode 100644
index 0000000..905e5d1
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/chains/Arbitrum.kt
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.chains
+
+object Arbitrum : Chain() {
+    override val chainId: Long
+        get() = 42161
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/chains/ArbitrumSepolia.kt b/lib/src/main/java/com/circle/modularwallets/core/chains/ArbitrumSepolia.kt
new file mode 100644
index 0000000..ceff56f
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/chains/ArbitrumSepolia.kt
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.chains
+
+object ArbitrumSepolia : Chain() {
+    override val chainId: Long
+        get() = 421614
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/chains/Chain.kt b/lib/src/main/java/com/circle/modularwallets/core/chains/Chain.kt
new file mode 100644
index 0000000..ec68fa1
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/chains/Chain.kt
@@ -0,0 +1,28 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.chains
+
+/**
+ * Abstract class representing a blockchain.
+ *
+ * @property chainId The unique identifier for the blockchain.
+ */
+abstract class Chain {
+    abstract val chainId: Long
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/chains/Mainnet.kt b/lib/src/main/java/com/circle/modularwallets/core/chains/Mainnet.kt
new file mode 100644
index 0000000..4a82d15
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/chains/Mainnet.kt
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.chains
+
+object Mainnet : Chain() {
+    override val chainId: Long
+        get() = 1
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/chains/Polygon.kt b/lib/src/main/java/com/circle/modularwallets/core/chains/Polygon.kt
new file mode 100644
index 0000000..f479e28
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/chains/Polygon.kt
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.chains
+
+object Polygon : Chain() {
+    override val chainId: Long
+        get() = 137
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/chains/PolygonAmoy.kt b/lib/src/main/java/com/circle/modularwallets/core/chains/PolygonAmoy.kt
new file mode 100644
index 0000000..cc7ea3a
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/chains/PolygonAmoy.kt
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.chains
+
+object PolygonAmoy : Chain() {
+    override val chainId: Long
+        get() = 80_002
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/chains/Sepolia.kt b/lib/src/main/java/com/circle/modularwallets/core/chains/Sepolia.kt
new file mode 100644
index 0000000..026f6b0
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/chains/Sepolia.kt
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.chains
+
+object Sepolia : Chain() {
+    override val chainId: Long
+        get() = 11155111
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/clients/BundlerClient.kt b/lib/src/main/java/com/circle/modularwallets/core/clients/BundlerClient.kt
new file mode 100644
index 0000000..f0e7758
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/clients/BundlerClient.kt
@@ -0,0 +1,391 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.clients
+
+import android.content.Context
+import com.circle.modularwallets.core.accounts.SmartAccount
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.circle.modularwallets.core.apis.bundler.BundlerApi
+import com.circle.modularwallets.core.apis.bundler.BundlerApiImpl
+import com.circle.modularwallets.core.apis.bundler.toResult
+import com.circle.modularwallets.core.apis.bundler.toUserOperationReceipt
+import com.circle.modularwallets.core.apis.public.PublicApi
+import com.circle.modularwallets.core.apis.public.PublicApiImpl
+import com.circle.modularwallets.core.apis.util.UtilApi
+import com.circle.modularwallets.core.apis.util.UtilApiImpl
+import com.circle.modularwallets.core.chains.Chain
+import com.circle.modularwallets.core.models.Block
+import com.circle.modularwallets.core.models.EncodeCallDataArg
+import com.circle.modularwallets.core.models.EntryPoint
+import com.circle.modularwallets.core.models.EstimateFeesPerGasResult
+import com.circle.modularwallets.core.models.EstimateUserOperationGasResult
+import com.circle.modularwallets.core.models.GetUserOperationResult
+import com.circle.modularwallets.core.models.Paymaster
+import com.circle.modularwallets.core.models.UserOperationReceipt
+import com.circle.modularwallets.core.models.UserOperationV07
+import com.circle.modularwallets.core.models.toRpcUserOperation
+import com.circle.modularwallets.core.transports.Transport
+import com.circle.modularwallets.core.utils.encoding.hexToLong
+import java.math.BigInteger
+
+class BundlerClient(chain: Chain, transport: Transport) : Client(chain, transport) {
+    private val api: BundlerApi = BundlerApiImpl
+    private val pubApi: PublicApi = PublicApiImpl
+    private val utilApi: UtilApi = UtilApiImpl
+
+    /**
+     * Estimates the gas values for a User Operation to be executed successfully.
+     *
+     * @param account The Account to use for User Operation execution.
+     * @param calls The calls to execute in the User Operation.
+     * @param paymaster Sets Paymaster configuration for the User Operation.
+     * @param estimateFeesPerGas Prepares fee properties for the User Operation request. Not available in Java.
+     * @return The estimated gas values for the User Operation.
+     */
+
+    @Throws(Exception::class)
+    @JvmOverloads
+    suspend fun estimateUserOperationGas(
+        account: SmartAccount,
+        calls: Array<EncodeCallDataArg>,
+        paymaster: Paymaster? = null,
+        estimateFeesPerGas: (suspend (SmartAccount, BundlerClient, UserOperationV07) -> EstimateFeesPerGasResult)? = null
+    ): EstimateUserOperationGasResult {
+        val userOp = when (account.entryPoint) {
+            EntryPoint.V07 -> {
+                api.prepareUserOperation(
+                    transport,
+                    account,
+                    calls,
+                    UserOperationV07(),
+                    paymaster,
+                    this,
+                    estimateFeesPerGas
+                )
+            }
+        }
+        return api.estimateUserOperationGas(transport, userOp, account.entryPoint)
+    }
+
+    /**
+     * Returns the chain ID associated with the current network
+     *
+     * @return The current chain ID.
+     */
+
+    @Throws(Exception::class)
+    suspend fun getChainId(): Long {
+        val result = api.getChainId(transport)
+        return hexToLong(result)
+    }
+
+    /**
+     * Returns the EntryPoints that the bundler supports.
+     *
+     * @return The EntryPoints that the bundler supports.
+     */
+
+    @Throws(Exception::class)
+    suspend fun getSupportedEntryPoints(): ArrayList<String> {
+        return api.getSupportedEntryPoints(transport)
+    }
+
+    /**
+     * Retrieves information about a User Operation given a hash.
+     *
+     * @param userOpHash User Operation hash.
+     * @return User Operation information.
+     */
+
+    @Throws(Exception::class)
+    suspend fun getUserOperation(userOpHash: String): GetUserOperationResult {
+        return api.getUserOperation(transport, userOpHash).toResult()
+    }
+
+    /**
+     * Returns the User Operation Receipt given a User Operation hash.
+     *
+     * @param userOpHash User Operation hash.
+     * @return The User Operation receipt.
+     */
+
+    @Throws(Exception::class)
+    suspend fun getUserOperationReceipt(userOpHash: String): UserOperationReceipt {
+        return api.getUserOperationReceipt(transport, userOpHash).toUserOperationReceipt()
+    }
+
+    /**
+     * Broadcasts a User Operation to the Bundler.
+     *
+     * @param context The context used to launch any UI needed; use an activity context to make sure the UI will be launched within the same task stack
+     * @param account The Account to use for User Operation execution.
+     * @param calls The calls to execute in the User Operation
+     * @param partialUserOp The partial User Operation to be completed
+     * @param paymaster Sets Paymaster configuration for the User Operation.
+     * @param estimateFeesPerGas Prepares fee properties for the User Operation request. Not available in Java.
+     * @return The hash of the sent User Operation.
+     */
+    @ExcludeFromGeneratedCCReport
+    @Throws(Exception::class)
+    @JvmOverloads
+    suspend fun sendUserOperation(
+        context: Context,
+        account: SmartAccount,
+        calls: Array<EncodeCallDataArg>?,
+        partialUserOp: UserOperationV07 = UserOperationV07(),
+        paymaster: Paymaster? = null,
+        estimateFeesPerGas: (suspend (SmartAccount, BundlerClient, UserOperationV07) -> EstimateFeesPerGasResult)? = null
+    ): String {
+        if (!partialUserOp.signature.isNullOrBlank()) {
+            return api.sendUserOperation(
+                transport,
+                partialUserOp.toRpcUserOperation(),
+                account.entryPoint.address
+            )
+        }
+        val userOp = when (account.entryPoint) {
+            EntryPoint.V07 -> {
+                api.prepareUserOperation(
+                    transport,
+                    account,
+                    calls,
+                    partialUserOp,
+                    paymaster,
+                    this,
+                    estimateFeesPerGas
+                )
+            }
+        }
+        userOp.signature = account.signUserOperation(context, chain.chainId, userOp)
+        return api.sendUserOperation(
+            transport,
+            userOp.toRpcUserOperation(),
+            account.entryPoint.address
+        )
+    }
+
+    /**
+     * Prepares a User Operation for execution and fills in missing properties.
+     *
+     * @param account The Account to use for User Operation execution.
+     * @param calls The calls to execute in the User Operation
+     * @param partialUserOp The partial User Operation to be completed
+     * @param paymaster Sets Paymaster configuration for the User Operation.
+     * @param estimateFeesPerGas Prepares fee properties for the User Operation request. Not available in Java.
+     * @return The prepared User Operation.
+     */
+
+    @Throws(Exception::class)
+    @JvmOverloads
+    suspend fun prepareUserOperation(
+        account: SmartAccount,
+        calls: Array<EncodeCallDataArg>?,
+        partialUserOp: UserOperationV07,
+        paymaster: Paymaster? = null,
+        estimateFeesPerGas: (suspend (SmartAccount, BundlerClient, UserOperationV07) -> EstimateFeesPerGasResult)? = null
+    ): UserOperationV07 {
+        return api.prepareUserOperation(
+            transport,
+            account,
+            calls,
+            partialUserOp,
+            paymaster,
+            this,
+            estimateFeesPerGas
+        )
+    }
+
+    /**
+     * Waits for the User Operation to be included on a Block (one confirmation), and then returns the User Operation receipt.
+     *
+     * @param userOpHash A User Operation hash.
+     * @param pollingInterval Polling frequency (in ms).
+     * @param retryCount The number of times to retry.
+     * @param timeout Optional timeout (in ms) to wait before stopping polling.
+     * @return The User Operation receipt.
+     */
+
+    @Throws(Exception::class)
+    @JvmOverloads
+    suspend fun waitForUserOperationReceipt(
+        userOpHash: String,
+        pollingInterval: Long = 4000,
+        retryCount: Int = 6,
+        timeout: Long? = null
+    ): UserOperationReceipt {
+        return api.waitForUserOperationReceipt(
+            transport,
+            userOpHash,
+            pollingInterval,
+            retryCount,
+            timeout
+        ).toUserOperationReceipt()
+    }
+
+    /**
+     * Retrieves the balance of the specified address at a given block tag.
+     *
+     * @param address The address to query the balance for. Only wallet addresses that registered with the using client key can be retrieved
+     * @param blockNumber The balance of the account at a block number.
+     * @return The balance of the address in wei.
+     */
+
+    @Throws(Exception::class)
+    suspend fun getBalance(address: String, blockNumber: BigInteger): BigInteger {
+        val result = pubApi.getBalance(transport, address, blockNumber)
+        return result
+    }
+
+    /**
+     * Retrieves the balance of the specified address at a given block tag.
+     *
+     * @param address The address to query the balance for. Only wallet addresses that registered with the using client key can be retrieved
+     * @param blockTag The balance of the account at a block tag.
+     * @return The balance of the address in wei.
+     */
+
+    @Throws(Exception::class)
+    @JvmOverloads
+    suspend fun getBalance(address: String, blockTag: String = "latest"): BigInteger {
+        val result = pubApi.getBalance(transport, address, blockTag)
+        return result
+    }
+
+    /**
+     * Returns the number of the most recent block seen.
+     *
+     * @return The number of the block.
+     */
+
+    @Throws(Exception::class)
+    suspend fun getBlockNumber(): BigInteger {
+        val result = pubApi.getBlockNum(transport)
+        return result
+    }
+
+    /**
+     * Returns the current price of gas (in wei).
+     *
+     * @return The gas price (in wei).
+     */
+
+    @Throws(Exception::class)
+    suspend fun getGasPrice(): BigInteger {
+        val result = pubApi.getGasPrice(transport)
+        return result
+    }
+
+    /**
+     * Executes a new message call immediately without submitting a transaction to the network.
+     *
+     * @param from The Account to call from.
+     * @param to The contract address or recipient.
+     * @param data A contract hashed method call with encoded args.
+     * @return The result of the call.
+     */
+
+    @Throws(Exception::class)
+    suspend fun call(
+        from: String?,
+        to: String,
+        data: String
+    ): String {
+        return pubApi.call(transport, from, to, data)
+    }
+
+    /**
+     * Retrieves the bytecode at an address.
+     *
+     * @param address The contract address.
+     * @param blockNumber The block number to perform the bytecode read against.
+     * @return The code of the specified address at the given block number.
+     */
+
+    @Throws(Exception::class)
+    suspend fun getCode(
+        address: String,
+        blockNumber: BigInteger
+    ): String {
+        return pubApi.getCode(transport, address, blockNumber)
+    }
+
+    /**
+     * Retrieves the bytecode at an address.
+     *
+     * @param address The contract address.
+     * @param blockTag The block tag to perform the bytecode read against.
+     * @return The code of the specified address at the given block tag.
+     */
+
+    @Throws(Exception::class)
+    @JvmOverloads
+    suspend fun getCode(
+        address: String,
+        blockTag: String = "latest"
+    ): String {
+        return pubApi.getCode(transport, address, blockTag)
+    }
+
+    /**
+     * Returns an estimate for the max priority fee per gas (in wei) for a transaction to be likely included in the next block.
+     * The Action will either call eth_maxPriorityFeePerGas (if supported) or manually calculate the max priority fee per gas based on the current block base fee per gas + gas price.
+     *
+     * @return An estimate (in wei) for the max priority fee per gas.
+     */
+
+    @Throws(Exception::class)
+    suspend fun estimateMaxPriorityFeePerGas(
+    ): BigInteger {
+        return utilApi.getMaxPriorityFeePerGas(transport)
+    }
+
+    /**
+     * Returns information about a block at a given block number.
+     *
+     * @param includeTransactions Whether or not to include transactions (as a structured array of Transaction objects). Default is false.
+     * @param blockNumber The block number to query the information for.
+     * @return Information about the block.
+     */
+
+    @Throws(Exception::class)
+    @JvmOverloads
+    suspend fun getBlock(
+        includeTransactions: Boolean = false,
+        blockNumber: BigInteger
+    ): Block {
+        return pubApi.getBlock(transport, includeTransactions, blockNumber)
+    }
+
+    /**
+     * Returns information about a block at a given block tag.
+     *
+     * @param includeTransactions Whether or not to include transactions (as a structured array of Transaction objects). Default is false.
+     * @param blockTag The block tag to query the information for. Default is "latest".
+     * @return Information about the block.
+     */
+
+    @Throws(Exception::class)
+    @JvmOverloads
+    suspend fun getBlock(
+        includeTransactions: Boolean = false,
+        blockTag: String = "latest"
+    ): Block {
+        return pubApi.getBlock(transport, includeTransactions, blockTag)
+    }
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/clients/Client.kt b/lib/src/main/java/com/circle/modularwallets/core/clients/Client.kt
new file mode 100644
index 0000000..ddc04a1
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/clients/Client.kt
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.clients
+
+import com.circle.modularwallets.core.chains.Chain
+import com.circle.modularwallets.core.transports.Transport
+
+/**
+ * Represents a client that interacts with a blockchain.
+ *
+ * @property chain The blockchain that the client interacts with.
+ * @property transport The transport mechanism used for making RPC requests.
+ */
+open class Client(val chain: Chain, val transport: Transport)
diff --git a/lib/src/main/java/com/circle/modularwallets/core/clients/PaymasterClient.kt b/lib/src/main/java/com/circle/modularwallets/core/clients/PaymasterClient.kt
new file mode 100644
index 0000000..71827fc
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/clients/PaymasterClient.kt
@@ -0,0 +1,76 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.clients
+
+import com.circle.modularwallets.core.apis.paymaster.PaymasterApi
+import com.circle.modularwallets.core.apis.paymaster.PaymasterApiImpl
+import com.circle.modularwallets.core.apis.paymaster.toResult
+import com.circle.modularwallets.core.chains.Chain
+import com.circle.modularwallets.core.models.EntryPoint
+import com.circle.modularwallets.core.models.GetPaymasterDataResult
+import com.circle.modularwallets.core.models.GetPaymasterStubDataResult
+import com.circle.modularwallets.core.models.IEntryPoint
+import com.circle.modularwallets.core.models.UserOperation
+import com.circle.modularwallets.core.transports.Transport
+
+class PaymasterClient(chain: Chain, transport: Transport) : Client(chain, transport) {
+    private val api: PaymasterApi = PaymasterApiImpl
+
+    /**
+     * Retrieves Paymaster data for a given User Operation.
+     *
+     * @param T The User Operation to retrieve Paymaster data for. Type T must be the subclass of UserOperation
+     * @param userOp The User Operation to retrieve Paymaster data for.
+     * @param entryPoint EntryPoint address to target.
+     * @param context Paymaster specific fields.
+     * @return Paymaster-related User Operation properties.
+     */
+
+    @Throws(Exception::class)
+    @JvmOverloads
+    suspend fun <T : UserOperation> getPaymasterData(
+        userOp: T,
+        entryPoint: EntryPoint,
+        context: Map<String, Any>? = null
+    ): GetPaymasterDataResult {
+        return api.getPaymasterData(transport, userOp, entryPoint, chain.chainId, context)
+            .toResult()
+    }
+
+    /**
+     * Retrieves Paymaster stub data for a given User Operation.
+     *
+     * @param T The User Operation to retrieve Paymaster stub data for. Type T must be the subclass of UserOperation.
+     * @param userOp The User Operation to retrieve Paymaster stub data for.
+     * @param entryPoint EntryPoint address to target.
+     * @param context Paymaster specific fields.
+     * @return Paymaster-related User Operation properties.
+     */
+
+    @Throws(Exception::class)
+    @JvmOverloads
+    suspend fun <T : UserOperation> getPaymasterStubData(
+        userOp: T,
+        entryPoint: IEntryPoint,
+        context: Map<String, Any>? = null
+    ): GetPaymasterStubDataResult {
+        return api.getPaymasterStubData(transport, userOp, entryPoint, chain.chainId, context)
+            .toResult()
+    }
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/constants/AbiConstants.kt b/lib/src/main/java/com/circle/modularwallets/core/constants/AbiConstants.kt
new file mode 100644
index 0000000..24a07b1
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/constants/AbiConstants.kt
@@ -0,0 +1,1843 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.constants
+
+import com.circle.modularwallets.core.models.Token
+
+val ABI_FUNCTION_TRANSFER = "transfer"
+
+internal val CONTRACT_ADDRESS: Map<String, String> = mapOf(
+    Token.Arbitrum_USDC.name to "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
+    Token.Arbitrum_ARB.name to "0x912CE59144191C1204E64559FE8253a0e49E6548",
+    Token.ArbitrumSepolia_USDC.name to "0x75faf114eafb1BDbe2F0316DF893fd58CE46AA4d",
+    Token.Polygon_USDC.name to "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
+    Token.PolygonAmoy_USDC.name to "0x41e94eb019c0762f9bfcf9fb1e58725bfb0e7582",
+)
+val CIRCLE_PLUGIN_ADD_OWNERS_ABI = """
+[
+  {
+    "inputs": [
+      {
+        "internalType": "address[]",
+        "name": "ownersToAdd",
+        "type": "address[]"
+      },
+      {
+        "internalType": "uint256[]",
+        "name": "weightsToAdd",
+        "type": "uint256[]"
+      },
+      {
+        "components": [
+          {
+            "internalType": "uint256",
+            "name": "x",
+            "type": "uint256"
+          },
+          {
+            "internalType": "uint256",
+            "name": "y",
+            "type": "uint256"
+          }
+        ],
+        "internalType": "struct PublicKey[]",
+        "name": "publicKeyOwnersToAdd",
+        "type": "tuple[]"
+      },
+      {
+        "internalType": "uint256[]",
+        "name": "pubicKeyWeightsToAdd",
+        "type": "uint256[]"
+      },
+      {
+        "internalType": "uint256",
+        "name": "newThresholdWeight",
+        "type": "uint256"
+      }
+    ],
+    "name": "addOwners",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  }
+]    
+""".trimIndent()
+val ABI_ERC20 = """
+[
+  {
+    "type": "event",
+    "name": "Approval",
+    "inputs": [
+      {
+        "indexed": true,
+        "name": "owner",
+        "type": "address"
+      },
+      {
+        "indexed": true,
+        "name": "spender",
+        "type": "address"
+      },
+      {
+        "indexed": false,
+        "name": "value",
+        "type": "uint256"
+      }
+    ]
+  },
+  {
+    "type": "event",
+    "name": "Transfer",
+    "inputs": [
+      {
+        "indexed": true,
+        "name": "from",
+        "type": "address"
+      },
+      {
+        "indexed": true,
+        "name": "to",
+        "type": "address"
+      },
+      {
+        "indexed": false,
+        "name": "value",
+        "type": "uint256"
+      }
+    ]
+  },
+  {
+    "type": "function",
+    "name": "allowance",
+    "stateMutability": "view",
+    "inputs": [
+      {
+        "name": "owner",
+        "type": "address"
+      },
+      {
+        "name": "spender",
+        "type": "address"
+      }
+    ],
+    "outputs": [
+      {
+        "name": "",
+        "type": "uint256"
+      }
+    ]
+  },
+  {
+    "type": "function",
+    "name": "approve",
+    "stateMutability": "nonpayable",
+    "inputs": [
+      {
+        "name": "spender",
+        "type": "address"
+      },
+      {
+        "name": "amount",
+        "type": "uint256"
+      }
+    ],
+    "outputs": [
+      {
+        "name": "",
+        "type": "bool"
+      }
+    ]
+  },
+  {
+    "type": "function",
+    "name": "balanceOf",
+    "stateMutability": "view",
+    "inputs": [
+      {
+        "name": "account",
+        "type": "address"
+      }
+    ],
+    "outputs": [
+      {
+        "name": "",
+        "type": "uint256"
+      }
+    ]
+  },
+  {
+    "type": "function",
+    "name": "decimals",
+    "stateMutability": "view",
+    "inputs": [],
+    "outputs": [
+      {
+        "name": "",
+        "type": "uint8"
+      }
+    ]
+  },
+  {
+    "type": "function",
+    "name": "name",
+    "stateMutability": "view",
+    "inputs": [],
+    "outputs": [
+      {
+        "name": "",
+        "type": "string"
+      }
+    ]
+  },
+  {
+    "type": "function",
+    "name": "symbol",
+    "stateMutability": "view",
+    "inputs": [],
+    "outputs": [
+      {
+        "name": "",
+        "type": "string"
+      }
+    ]
+  },
+  {
+    "type": "function",
+    "name": "totalSupply",
+    "stateMutability": "view",
+    "inputs": [],
+    "outputs": [
+      {
+        "name": "",
+        "type": "uint256"
+      }
+    ]
+  },
+  {
+    "type": "function",
+    "name": "transfer",
+    "stateMutability": "nonpayable",
+    "inputs": [
+      {
+        "name": "recipient",
+        "type": "address"
+      },
+      {
+        "name": "amount",
+        "type": "uint256"
+      }
+    ],
+    "outputs": [
+      {
+        "name": "",
+        "type": "bool"
+      }
+    ]
+  },
+  {
+    "type": "function",
+    "name": "transferFrom",
+    "stateMutability": "nonpayable",
+    "inputs": [
+      {
+        "name": "sender",
+        "type": "address"
+      },
+      {
+        "name": "recipient",
+        "type": "address"
+      },
+      {
+        "name": "amount",
+        "type": "uint256"
+      }
+    ],
+    "outputs": [
+      {
+        "name": "",
+        "type": "bool"
+      }
+    ]
+  }
+]
+""".trimIndent()
+
+val CIRCLE_MSCA_6900_V1_EP07_FACTORY_ABI = """
+[
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "_owner",
+        "type": "address"
+      },
+      {
+        "internalType": "address",
+        "name": "_entryPointAddr",
+        "type": "address"
+      },
+      {
+        "internalType": "address",
+        "name": "_pluginManagerAddr",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "nonpayable",
+    "type": "constructor"
+  },
+  {
+    "inputs": [],
+    "name": "Create2FailedDeployment",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "InvalidInitializationInput",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "InvalidLength",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "owner",
+        "type": "address"
+      }
+    ],
+    "name": "OwnableInvalidOwner",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "account",
+        "type": "address"
+      }
+    ],
+    "name": "OwnableUnauthorizedAccount",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "plugin",
+        "type": "address"
+      }
+    ],
+    "name": "PluginIsNotAllowed",
+    "type": "error"
+  },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "proxy",
+        "type": "address"
+      },
+      {
+        "indexed": false,
+        "internalType": "bytes32",
+        "name": "sender",
+        "type": "bytes32"
+      },
+      {
+        "indexed": false,
+        "internalType": "bytes32",
+        "name": "salt",
+        "type": "bytes32"
+      }
+    ],
+    "name": "AccountCreated",
+    "type": "event"
+  },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "factory",
+        "type": "address"
+      },
+      {
+        "indexed": false,
+        "internalType": "address",
+        "name": "accountImplementation",
+        "type": "address"
+      },
+      {
+        "indexed": false,
+        "internalType": "address",
+        "name": "entryPoint",
+        "type": "address"
+      }
+    ],
+    "name": "FactoryDeployed",
+    "type": "event"
+  },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "previousOwner",
+        "type": "address"
+      },
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "newOwner",
+        "type": "address"
+      }
+    ],
+    "name": "OwnershipTransferStarted",
+    "type": "event"
+  },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "previousOwner",
+        "type": "address"
+      },
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "newOwner",
+        "type": "address"
+      }
+    ],
+    "name": "OwnershipTransferred",
+    "type": "event"
+  },
+  {
+    "inputs": [],
+    "name": "ACCOUNT_IMPLEMENTATION",
+    "outputs": [
+      {
+        "internalType": "contract UpgradableMSCA",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "ENTRY_POINT",
+    "outputs": [
+      {
+        "internalType": "contract IEntryPoint",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "acceptOwnership",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "uint32",
+        "name": "_unstakeDelaySec",
+        "type": "uint32"
+      }
+    ],
+    "name": "addStake",
+    "outputs": [],
+    "stateMutability": "payable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "bytes32",
+        "name": "_sender",
+        "type": "bytes32"
+      },
+      {
+        "internalType": "bytes32",
+        "name": "_salt",
+        "type": "bytes32"
+      },
+      {
+        "internalType": "bytes",
+        "name": "_initializingData",
+        "type": "bytes"
+      }
+    ],
+    "name": "createAccount",
+    "outputs": [
+      {
+        "internalType": "contract UpgradableMSCA",
+        "name": "account",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "bytes32",
+        "name": "_sender",
+        "type": "bytes32"
+      },
+      {
+        "internalType": "bytes32",
+        "name": "_salt",
+        "type": "bytes32"
+      },
+      {
+        "internalType": "bytes",
+        "name": "_initializingData",
+        "type": "bytes"
+      }
+    ],
+    "name": "getAddress",
+    "outputs": [
+      {
+        "internalType": "address",
+        "name": "addr",
+        "type": "address"
+      },
+      {
+        "internalType": "bytes32",
+        "name": "mixedSalt",
+        "type": "bytes32"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "name": "isPluginAllowed",
+    "outputs": [
+      {
+        "internalType": "bool",
+        "name": "",
+        "type": "bool"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "owner",
+    "outputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "pendingOwner",
+    "outputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "renounceOwnership",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address[]",
+        "name": "_plugins",
+        "type": "address[]"
+      },
+      {
+        "internalType": "bool[]",
+        "name": "_permissions",
+        "type": "bool[]"
+      }
+    ],
+    "name": "setPlugins",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "newOwner",
+        "type": "address"
+      }
+    ],
+    "name": "transferOwnership",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "unlockStake",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address payable",
+        "name": "_withdrawAddress",
+        "type": "address"
+      }
+    ],
+    "name": "withdrawStake",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  }
+]
+""".trimIndent()
+val CIRCLE_MSCA_6900_V1_EP07_ABI = """
+[
+  {
+    "inputs": [
+      {
+        "internalType": "contract IEntryPoint",
+        "name": "_newEntryPoint",
+        "type": "address"
+      },
+      {
+        "internalType": "contract PluginManager",
+        "name": "_newPluginManager",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "nonpayable",
+    "type": "constructor"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "target",
+        "type": "address"
+      }
+    ],
+    "name": "AddressEmptyCode",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "implementation",
+        "type": "address"
+      }
+    ],
+    "name": "ERC1967InvalidImplementation",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "ERC1967NonPayable",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "plugin",
+        "type": "address"
+      },
+      {
+        "internalType": "bytes4",
+        "name": "selector",
+        "type": "bytes4"
+      }
+    ],
+    "name": "ExecFromPluginToSelectorNotPermitted",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "ExecuteFromPluginToExternalNotPermitted",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "FailedInnerCall",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "InvalidAuthorizer",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "bytes4",
+        "name": "selector",
+        "type": "bytes4"
+      }
+    ],
+    "name": "InvalidExecutionFunction",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "uint8",
+        "name": "functionId",
+        "type": "uint8"
+      }
+    ],
+    "name": "InvalidHookFunctionId",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "InvalidInitialization",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "InvalidInitializationInput",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "InvalidLimit",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "uint8",
+        "name": "functionId",
+        "type": "uint8"
+      }
+    ],
+    "name": "InvalidValidationFunctionId",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "plugin",
+        "type": "address"
+      }
+    ],
+    "name": "NativeTokenSpendingNotPermitted",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "NotFoundSelector",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "NotInitializing",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "bytes4",
+        "name": "selector",
+        "type": "bytes4"
+      }
+    ],
+    "name": "NotNativeFunctionSelector",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "plugin",
+        "type": "address"
+      },
+      {
+        "internalType": "uint8",
+        "name": "functionId",
+        "type": "uint8"
+      },
+      {
+        "internalType": "bytes",
+        "name": "revertReason",
+        "type": "bytes"
+      }
+    ],
+    "name": "PostExecHookFailed",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "plugin",
+        "type": "address"
+      },
+      {
+        "internalType": "uint8",
+        "name": "functionId",
+        "type": "uint8"
+      },
+      {
+        "internalType": "bytes",
+        "name": "revertReason",
+        "type": "bytes"
+      }
+    ],
+    "name": "PreExecHookFailed",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "plugin",
+        "type": "address"
+      },
+      {
+        "internalType": "uint8",
+        "name": "functionId",
+        "type": "uint8"
+      },
+      {
+        "internalType": "bytes",
+        "name": "revertReason",
+        "type": "bytes"
+      }
+    ],
+    "name": "PreRuntimeValidationHookFailed",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "plugin",
+        "type": "address"
+      },
+      {
+        "internalType": "uint8",
+        "name": "functionId",
+        "type": "uint8"
+      },
+      {
+        "internalType": "bytes",
+        "name": "revertReason",
+        "type": "bytes"
+      }
+    ],
+    "name": "RuntimeValidationFailed",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "plugin",
+        "type": "address"
+      }
+    ],
+    "name": "TargetIsPlugin",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "UUPSUnauthorizedCallContext",
+    "type": "error"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "bytes32",
+        "name": "slot",
+        "type": "bytes32"
+      }
+    ],
+    "name": "UUPSUnsupportedProxiableUUID",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "UnauthorizedCaller",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "WalletStorageIsInitialized",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "WalletStorageIsInitializing",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "WalletStorageIsNotInitializing",
+    "type": "error"
+  },
+  {
+    "inputs": [],
+    "name": "WrongTimeBounds",
+    "type": "error"
+  },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": false,
+        "internalType": "uint64",
+        "name": "version",
+        "type": "uint64"
+      }
+    ],
+    "name": "Initialized",
+    "type": "event"
+  },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "plugin",
+        "type": "address"
+      },
+      {
+        "indexed": false,
+        "internalType": "bytes32",
+        "name": "manifestHash",
+        "type": "bytes32"
+      },
+      {
+        "components": [
+          {
+            "internalType": "address",
+            "name": "plugin",
+            "type": "address"
+          },
+          {
+            "internalType": "uint8",
+            "name": "functionId",
+            "type": "uint8"
+          }
+        ],
+        "indexed": false,
+        "internalType": "struct FunctionReference[]",
+        "name": "dependencies",
+        "type": "tuple[]"
+      }
+    ],
+    "name": "PluginInstalled",
+    "type": "event"
+  },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "plugin",
+        "type": "address"
+      },
+      {
+        "indexed": true,
+        "internalType": "bool",
+        "name": "onUninstallSucceeded",
+        "type": "bool"
+      }
+    ],
+    "name": "PluginUninstalled",
+    "type": "event"
+  },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "account",
+        "type": "address"
+      },
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "entryPointAddress",
+        "type": "address"
+      }
+    ],
+    "name": "UpgradableMSCAInitialized",
+    "type": "event"
+  },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "implementation",
+        "type": "address"
+      }
+    ],
+    "name": "Upgraded",
+    "type": "event"
+  },
+  {
+    "anonymous": false,
+    "inputs": [],
+    "name": "WalletStorageInitialized",
+    "type": "event"
+  },
+  {
+    "stateMutability": "payable",
+    "type": "fallback"
+  },
+  {
+    "inputs": [],
+    "name": "AUTHOR",
+    "outputs": [
+      {
+        "internalType": "string",
+        "name": "",
+        "type": "string"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "ENTRY_POINT",
+    "outputs": [
+      {
+        "internalType": "contract IEntryPoint",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "PLUGIN_MANAGER",
+    "outputs": [
+      {
+        "internalType": "contract PluginManager",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "UPGRADE_INTERFACE_VERSION",
+    "outputs": [
+      {
+        "internalType": "string",
+        "name": "",
+        "type": "string"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "VERSION",
+    "outputs": [
+      {
+        "internalType": "string",
+        "name": "",
+        "type": "string"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "addDeposit",
+    "outputs": [],
+    "stateMutability": "payable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "target",
+        "type": "address"
+      },
+      {
+        "internalType": "uint256",
+        "name": "value",
+        "type": "uint256"
+      },
+      {
+        "internalType": "bytes",
+        "name": "data",
+        "type": "bytes"
+      }
+    ],
+    "name": "execute",
+    "outputs": [
+      {
+        "internalType": "bytes",
+        "name": "returnData",
+        "type": "bytes"
+      }
+    ],
+    "stateMutability": "payable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "components": [
+          {
+            "internalType": "address",
+            "name": "target",
+            "type": "address"
+          },
+          {
+            "internalType": "uint256",
+            "name": "value",
+            "type": "uint256"
+          },
+          {
+            "internalType": "bytes",
+            "name": "data",
+            "type": "bytes"
+          }
+        ],
+        "internalType": "struct Call[]",
+        "name": "calls",
+        "type": "tuple[]"
+      }
+    ],
+    "name": "executeBatch",
+    "outputs": [
+      {
+        "internalType": "bytes[]",
+        "name": "returnData",
+        "type": "bytes[]"
+      }
+    ],
+    "stateMutability": "payable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "bytes",
+        "name": "data",
+        "type": "bytes"
+      }
+    ],
+    "name": "executeFromPlugin",
+    "outputs": [
+      {
+        "internalType": "bytes",
+        "name": "",
+        "type": "bytes"
+      }
+    ],
+    "stateMutability": "payable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "target",
+        "type": "address"
+      },
+      {
+        "internalType": "uint256",
+        "name": "value",
+        "type": "uint256"
+      },
+      {
+        "internalType": "bytes",
+        "name": "data",
+        "type": "bytes"
+      }
+    ],
+    "name": "executeFromPluginExternal",
+    "outputs": [
+      {
+        "internalType": "bytes",
+        "name": "",
+        "type": "bytes"
+      }
+    ],
+    "stateMutability": "payable",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "getDeposit",
+    "outputs": [
+      {
+        "internalType": "uint256",
+        "name": "",
+        "type": "uint256"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "getEntryPoint",
+    "outputs": [
+      {
+        "internalType": "contract IEntryPoint",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "bytes4",
+        "name": "selector",
+        "type": "bytes4"
+      }
+    ],
+    "name": "getExecutionFunctionConfig",
+    "outputs": [
+      {
+        "components": [
+          {
+            "internalType": "address",
+            "name": "plugin",
+            "type": "address"
+          },
+          {
+            "components": [
+              {
+                "internalType": "address",
+                "name": "plugin",
+                "type": "address"
+              },
+              {
+                "internalType": "uint8",
+                "name": "functionId",
+                "type": "uint8"
+              }
+            ],
+            "internalType": "struct FunctionReference",
+            "name": "userOpValidationFunction",
+            "type": "tuple"
+          },
+          {
+            "components": [
+              {
+                "internalType": "address",
+                "name": "plugin",
+                "type": "address"
+              },
+              {
+                "internalType": "uint8",
+                "name": "functionId",
+                "type": "uint8"
+              }
+            ],
+            "internalType": "struct FunctionReference",
+            "name": "runtimeValidationFunction",
+            "type": "tuple"
+          }
+        ],
+        "internalType": "struct ExecutionFunctionConfig",
+        "name": "executionFunctionConfig",
+        "type": "tuple"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "bytes4",
+        "name": "selector",
+        "type": "bytes4"
+      }
+    ],
+    "name": "getExecutionHooks",
+    "outputs": [
+      {
+        "components": [
+          {
+            "components": [
+              {
+                "internalType": "address",
+                "name": "plugin",
+                "type": "address"
+              },
+              {
+                "internalType": "uint8",
+                "name": "functionId",
+                "type": "uint8"
+              }
+            ],
+            "internalType": "struct FunctionReference",
+            "name": "preExecHook",
+            "type": "tuple"
+          },
+          {
+            "components": [
+              {
+                "internalType": "address",
+                "name": "plugin",
+                "type": "address"
+              },
+              {
+                "internalType": "uint8",
+                "name": "functionId",
+                "type": "uint8"
+              }
+            ],
+            "internalType": "struct FunctionReference",
+            "name": "postExecHook",
+            "type": "tuple"
+          }
+        ],
+        "internalType": "struct ExecutionHooks[]",
+        "name": "executionHooks",
+        "type": "tuple[]"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "getInstalledPlugins",
+    "outputs": [
+      {
+        "internalType": "address[]",
+        "name": "pluginAddresses",
+        "type": "address[]"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "getNonce",
+    "outputs": [
+      {
+        "internalType": "uint256",
+        "name": "",
+        "type": "uint256"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "bytes4",
+        "name": "selector",
+        "type": "bytes4"
+      }
+    ],
+    "name": "getPreValidationHooks",
+    "outputs": [
+      {
+        "components": [
+          {
+            "internalType": "address",
+            "name": "plugin",
+            "type": "address"
+          },
+          {
+            "internalType": "uint8",
+            "name": "functionId",
+            "type": "uint8"
+          }
+        ],
+        "internalType": "struct FunctionReference[]",
+        "name": "preUserOpValidationHooks",
+        "type": "tuple[]"
+      },
+      {
+        "components": [
+          {
+            "internalType": "address",
+            "name": "plugin",
+            "type": "address"
+          },
+          {
+            "internalType": "uint8",
+            "name": "functionId",
+            "type": "uint8"
+          }
+        ],
+        "internalType": "struct FunctionReference[]",
+        "name": "preRuntimeValidationHooks",
+        "type": "tuple[]"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address[]",
+        "name": "plugins",
+        "type": "address[]"
+      },
+      {
+        "internalType": "bytes32[]",
+        "name": "manifestHashes",
+        "type": "bytes32[]"
+      },
+      {
+        "internalType": "bytes[]",
+        "name": "pluginInstallData",
+        "type": "bytes[]"
+      }
+    ],
+    "name": "initializeUpgradableMSCA",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "plugin",
+        "type": "address"
+      },
+      {
+        "internalType": "bytes32",
+        "name": "manifestHash",
+        "type": "bytes32"
+      },
+      {
+        "internalType": "bytes",
+        "name": "pluginInstallData",
+        "type": "bytes"
+      },
+      {
+        "components": [
+          {
+            "internalType": "address",
+            "name": "plugin",
+            "type": "address"
+          },
+          {
+            "internalType": "uint8",
+            "name": "functionId",
+            "type": "uint8"
+          }
+        ],
+        "internalType": "struct FunctionReference[]",
+        "name": "dependencies",
+        "type": "tuple[]"
+      }
+    ],
+    "name": "installPlugin",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      },
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      },
+      {
+        "internalType": "uint256[]",
+        "name": "",
+        "type": "uint256[]"
+      },
+      {
+        "internalType": "uint256[]",
+        "name": "",
+        "type": "uint256[]"
+      },
+      {
+        "internalType": "bytes",
+        "name": "",
+        "type": "bytes"
+      }
+    ],
+    "name": "onERC1155BatchReceived",
+    "outputs": [
+      {
+        "internalType": "bytes4",
+        "name": "",
+        "type": "bytes4"
+      }
+    ],
+    "stateMutability": "pure",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      },
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      },
+      {
+        "internalType": "uint256",
+        "name": "",
+        "type": "uint256"
+      },
+      {
+        "internalType": "uint256",
+        "name": "",
+        "type": "uint256"
+      },
+      {
+        "internalType": "bytes",
+        "name": "",
+        "type": "bytes"
+      }
+    ],
+    "name": "onERC1155Received",
+    "outputs": [
+      {
+        "internalType": "bytes4",
+        "name": "",
+        "type": "bytes4"
+      }
+    ],
+    "stateMutability": "pure",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      },
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      },
+      {
+        "internalType": "uint256",
+        "name": "",
+        "type": "uint256"
+      },
+      {
+        "internalType": "bytes",
+        "name": "",
+        "type": "bytes"
+      }
+    ],
+    "name": "onERC721Received",
+    "outputs": [
+      {
+        "internalType": "bytes4",
+        "name": "",
+        "type": "bytes4"
+      }
+    ],
+    "stateMutability": "pure",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "proxiableUUID",
+    "outputs": [
+      {
+        "internalType": "bytes32",
+        "name": "",
+        "type": "bytes32"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "bytes4",
+        "name": "interfaceId",
+        "type": "bytes4"
+      }
+    ],
+    "name": "supportsInterface",
+    "outputs": [
+      {
+        "internalType": "bool",
+        "name": "",
+        "type": "bool"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "operator",
+        "type": "address"
+      },
+      {
+        "internalType": "address",
+        "name": "from",
+        "type": "address"
+      },
+      {
+        "internalType": "address",
+        "name": "to",
+        "type": "address"
+      },
+      {
+        "internalType": "uint256",
+        "name": "amount",
+        "type": "uint256"
+      },
+      {
+        "internalType": "bytes",
+        "name": "userData",
+        "type": "bytes"
+      },
+      {
+        "internalType": "bytes",
+        "name": "operatorData",
+        "type": "bytes"
+      }
+    ],
+    "name": "tokensReceived",
+    "outputs": [],
+    "stateMutability": "pure",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "plugin",
+        "type": "address"
+      },
+      {
+        "internalType": "bytes",
+        "name": "config",
+        "type": "bytes"
+      },
+      {
+        "internalType": "bytes",
+        "name": "pluginUninstallData",
+        "type": "bytes"
+      }
+    ],
+    "name": "uninstallPlugin",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "newImplementation",
+        "type": "address"
+      },
+      {
+        "internalType": "bytes",
+        "name": "data",
+        "type": "bytes"
+      }
+    ],
+    "name": "upgradeToAndCall",
+    "outputs": [],
+    "stateMutability": "payable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "components": [
+          {
+            "internalType": "address",
+            "name": "sender",
+            "type": "address"
+          },
+          {
+            "internalType": "uint256",
+            "name": "nonce",
+            "type": "uint256"
+          },
+          {
+            "internalType": "bytes",
+            "name": "initCode",
+            "type": "bytes"
+          },
+          {
+            "internalType": "bytes",
+            "name": "callData",
+            "type": "bytes"
+          },
+          {
+            "internalType": "bytes32",
+            "name": "accountGasLimits",
+            "type": "bytes32"
+          },
+          {
+            "internalType": "uint256",
+            "name": "preVerificationGas",
+            "type": "uint256"
+          },
+          {
+            "internalType": "bytes32",
+            "name": "gasFees",
+            "type": "bytes32"
+          },
+          {
+            "internalType": "bytes",
+            "name": "paymasterAndData",
+            "type": "bytes"
+          },
+          {
+            "internalType": "bytes",
+            "name": "signature",
+            "type": "bytes"
+          }
+        ],
+        "internalType": "struct PackedUserOperation",
+        "name": "userOp",
+        "type": "tuple"
+      },
+      {
+        "internalType": "bytes32",
+        "name": "userOpHash",
+        "type": "bytes32"
+      },
+      {
+        "internalType": "uint256",
+        "name": "missingAccountFunds",
+        "type": "uint256"
+      }
+    ],
+    "name": "validateUserOp",
+    "outputs": [
+      {
+        "internalType": "uint256",
+        "name": "validationData",
+        "type": "uint256"
+      }
+    ],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address payable",
+        "name": "withdrawAddress",
+        "type": "address"
+      },
+      {
+        "internalType": "uint256",
+        "name": "amount",
+        "type": "uint256"
+      }
+    ],
+    "name": "withdrawDepositTo",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "stateMutability": "payable",
+    "type": "receive"
+  }
+] 
+""".trimIndent()
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/constants/MscaConstants.kt b/lib/src/main/java/com/circle/modularwallets/core/constants/MscaConstants.kt
new file mode 100644
index 0000000..9384208
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/constants/MscaConstants.kt
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.constants
+
+import com.circle.modularwallets.core.utils.data.pad
+import org.web3j.utils.Numeric
+import java.math.BigInteger
+
+val MINIMUM_VERIFICATION_GAS_LIMIT = BigInteger.valueOf(600_000)
+val MINIMUM_UNDEPLOY_VERIFICATION_GAS_LIMIT = BigInteger.valueOf(1_500_000)
+val SEPOLIA_MINIMUM_VERIFICATION_GAS_LIMIT = BigInteger.valueOf(600_000)
+val SEPOLIA_MINIMUM_UNDEPLOY_VERIFICATION_GAS_LIMIT = BigInteger.valueOf(2_000_000)
+val MAINNET_MINIMUM_VERIFICATION_GAS_LIMIT = BigInteger.valueOf(1_000_000)
+val MAINNET_MINIMUM_UNDEPLOY_VERIFICATION_GAS_LIMIT = BigInteger.valueOf(2_500_000)
+
+
+/** The Circle Upgradable MSCA Factory. */
+object FACTORY {
+    val abi = CIRCLE_MSCA_6900_V1_EP07_FACTORY_ABI
+    val address = "0x0000000DF7E6c9Dc387cAFc5eCBfa6c3a6179AdD"
+}
+
+/** The upgradable MSCA account implementation */
+object CIRCLE_WEIGHTED_WEB_AUTHN_MULTISIG_PLUGIN {
+    val address = "0x0000000C984AFf541D6cE86Bb697e68ec57873C8"
+    val manifestHash =
+        Numeric.hexStringToByteArray("0xa043327d77a74c1c55cfa799284b831fe09535a88b9f5fa4173d334e5ba0fd91")
+}
+
+object REPLAY_SAFE_HASH_V1 {
+    val name = "Weighted Multisig Webauthn Plugin"
+    val primaryType = "CircleWeightedWebauthnMultisigMessage"
+    val domainSeparatorType =
+        "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract,bytes32 salt)"
+    val moduleType = "CircleWeightedWebauthnMultisigMessage(bytes32 hash)"
+    val version = "1.0.0"
+}
+
+const val EIP712_PREFIX = "0x1901"
+val EIP1271_VALID_SIGNATURE = byteArrayOf(0x16, 0x26, 0xba.toByte(), 0x7e)
+
+/** The salt for the MSCA factory contract. */
+internal val SALT = Numeric.hexStringToByteArray(pad("0x", 32))
+
+/** The public key own weights. */
+val PUBLIC_KEY_OWN_WEIGHT = 1L
+
+/** The threshold weight. */
+val THRESHOLD_WEIGHT = 1L
+val STUB_SIGNATURE =
+    "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"
+const val CIRCLE_SMART_ACCOUNT_VERSION_V1 = "circle_passkey_account_v1"
+internal val CIRCLE_SMART_ACCOUNT_VERSION: Map<String, String> = mapOf(
+    CIRCLE_SMART_ACCOUNT_VERSION_V1 to "circle_6900_v1"
+)
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/constants/UnitConstants.kt b/lib/src/main/java/com/circle/modularwallets/core/constants/UnitConstants.kt
new file mode 100644
index 0000000..0bb5b69
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/constants/UnitConstants.kt
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.constants
+
+// Ether units
+internal val etherUnits: Map<String, Int> = mapOf(
+    "gwei" to 9,
+    "wei" to 18
+)
+
+// Gwei units
+internal val gweiUnits: Map<String, Int> = mapOf(
+    "ether" to -9,
+    "wei" to 9
+)
+
+// Wei units
+internal val weiUnits: Map<String, Int> = mapOf(
+    "ether" to -18,
+    "gwei" to -9
+)
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/errors/AddressErrors.kt b/lib/src/main/java/com/circle/modularwallets/core/errors/AddressErrors.kt
new file mode 100644
index 0000000..c6997d7
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/errors/AddressErrors.kt
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.errors
+
+open class InvalidAddressError(
+    address: String
+) : BaseError(
+    "Address \"$address\" is invalid.",
+    BaseErrorParameters(
+        metaMessages = mutableListOf(
+            "- Address must be a hex value of 20 bytes (40 hex characters).",
+            "- Address must match its checksum counterpart."
+        ),
+        name = "InvalidAddressError"
+    )
+)
diff --git a/lib/src/main/java/com/circle/modularwallets/core/errors/BaseError.kt b/lib/src/main/java/com/circle/modularwallets/core/errors/BaseError.kt
new file mode 100644
index 0000000..e5f12b9
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/errors/BaseError.kt
@@ -0,0 +1,90 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.errors
+
+import com.circle.modularwallets.core.BuildConfig
+
+data class BaseErrorParameters(
+    val cause: Throwable? = null,
+    val details: String? = null,
+    val metaMessages: MutableList<String>? = null,
+    val name: String = "BaseError",
+)
+
+open class BaseError(
+    open val shortMessage: String,
+    args: BaseErrorParameters = BaseErrorParameters()
+) : Exception(buildMessage(shortMessage, args), args.cause) {
+
+    val details: String? = getDetails(args)
+    val metaMessages: MutableList<String>? = args.metaMessages
+    open val name: String = args.name
+
+    companion object {
+        private fun getDetails(args: BaseErrorParameters): String? {
+            return when {
+                args.cause is BaseError -> args.cause.details
+                args.cause?.message != null -> args.cause.message
+                else -> args.details
+            }
+        }
+
+        private fun buildMessage(shortMessage: String, args: BaseErrorParameters): String {
+            val messageParts = mutableListOf<String>()
+            messageParts.add("${args.name}: " + (shortMessage.takeIf { it.isNotEmpty() }
+                ?: "An error occurred."))
+            if (messageParts.isNotEmpty() && !messageParts.last().endsWith("\n")) {
+                messageParts[messageParts.lastIndex] = messageParts.last() + "\n"
+            }
+
+            args.metaMessages?.let {
+                messageParts.addAll(it)
+            }
+
+            if (messageParts.isNotEmpty() && !messageParts.last().endsWith("\n")) {
+                messageParts[messageParts.lastIndex] = messageParts.last() + "\n"
+            }
+
+            val details = getDetails(args)
+            details?.let {
+                messageParts.add("Details: $it")
+            }
+
+            messageParts.add("Version: ${BuildConfig.version}")
+
+            return messageParts.joinToString("\n")
+        }
+    }
+
+    fun walk(fn: ((Throwable?) -> Boolean)? = null): Throwable? {
+        return walk(this, fn)
+    }
+}
+
+fun walk(
+    err: Throwable? = null,
+    fn: ((Throwable?) -> Boolean)? = null
+): Throwable? {
+    if (fn?.invoke(err) == true) return err
+    err?.cause?.let {
+        return walk(it, fn)
+    }
+    return if (fn != null) null else err
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/errors/BundlerErrors.kt b/lib/src/main/java/com/circle/modularwallets/core/errors/BundlerErrors.kt
new file mode 100644
index 0000000..29ac29d
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/errors/BundlerErrors.kt
@@ -0,0 +1,646 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.errors
+
+import java.math.BigInteger
+
+open class AccountNotDeployedError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Smart Account is not deployed.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- No `factory`/`factoryData` or `initCode` properties are provided for Smart Account deployment.",
+            "- An incorrect `sender` address is provided.",
+        ),
+        name = "AccountNotDeployedError"
+    )
+) {
+    companion object {
+        const val message = "aa20"
+    }
+}
+
+open class ExecutionRevertedError(
+    cause: BaseError? = null,
+    message: String? = null
+) : BaseError(
+    getMessage(message),
+    BaseErrorParameters(
+        cause,
+        name = "ExecutionRevertedError"
+    )
+) {
+    companion object {
+        const val code: Int = -32521
+        const val message = "execution reverted"
+        fun getMessage(message: String? = null): String {
+
+            var reason = message
+                ?.replace("execution reverted: ", "")
+                ?.replace("execution reverted", "")
+            reason =
+                if (reason?.isNotEmpty() == true) "with reason: $reason" else "for an unknown reason"
+            return "Execution reverted $reason."
+        }
+    }
+
+}
+
+open class FailedToSendToBeneficiaryError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Failed to send funds to beneficiary.",
+    BaseErrorParameters(
+        cause,
+        name = "FailedToSendToBeneficiaryError"
+    )
+) {
+    companion object {
+        const val message = "aa91"
+    }
+}
+
+open class GasValuesOverflowError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Gas value overflowed.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- one of the gas values exceeded 2**120 (uint120)",
+        ),
+        name = "GasValuesOverflowError"
+    )
+) {
+    companion object {
+        const val message = "aa94"
+    }
+}
+
+open class HandleOpsOutOfGasError(
+    cause: BaseError? = null,
+) : BaseError(
+    "The `handleOps` function was called by the Bundler with a gas limit too low.",
+    BaseErrorParameters(
+        cause,
+        name = "HandleOpsOutOfGasError"
+    )
+) {
+    companion object {
+        const val message = "aa95"
+    }
+}
+
+open class InitCodeFailedError(
+    cause: BaseError? = null,
+    factory: String? = null,
+    factoryData: String? = null,
+    initCode: String? = null,
+) : BaseError(
+    "Failed to simulate deployment for Smart Account.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- Invalid `factory`/`factoryData` or `initCode` properties are present",
+            "- Smart Account deployment execution ran out of gas (low `verificationGasLimit` value)",
+            "- Smart Account deployment execution reverted with an error",
+        ).apply {
+            val rare = lastIndex
+            if (isNotEmpty() && !this[lastIndex].endsWith("\n")) {
+                this[lastIndex] = this[lastIndex] + "\n"
+            }
+
+            factory?.let { add("factory: $it") }
+            factoryData?.let { add("factoryData: $it") }
+            initCode?.let { add("initCode: $it") }
+
+            if (isNotEmpty() && rare != lastIndex && !this[lastIndex].endsWith("\n")) {
+                this[lastIndex] = this[lastIndex] + "\n"
+            }
+        },
+        name = "InitCodeFailedError"
+    )
+) {
+    companion object {
+        const val message = "aa13"
+    }
+}
+
+open class InitCodeMustCreateSenderError(
+    cause: BaseError? = null,
+    factory: String? = null,
+    factoryData: String? = null,
+    initCode: String? = null,
+) : BaseError(
+    "Smart Account initialization implementation did not create an account.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- `factory`/`factoryData` or `initCode` properties are invalid",
+            "- Smart Account initialization implementation is incorrect\n",
+        ).apply {
+            factory?.let { add("factory: $it") }
+            factoryData?.let { add("factoryData: $it") }
+            initCode?.let { add("initCode: $it") }
+        },
+        name = "InitCodeMustCreateSenderError"
+    )
+) {
+    companion object {
+        const val message = "aa15"
+    }
+}
+
+open class InitCodeMustReturnSenderError(
+    cause: BaseError? = null,
+    factory: String? = null,
+    factoryData: String? = null,
+    initCode: String? = null,
+    sender: String? = null,
+) : BaseError(
+    "Smart Account initialization implementation does not return the expected sender.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "Smart Account initialization implementation does not return a sender address\n",
+        ).apply {
+            factory?.let { add("factory: $it") }
+            factoryData?.let { add("factoryData: $it") }
+            initCode?.let { add("initCode: $it") }
+            sender?.let { add("sender: $it") }
+        },
+        name = "InitCodeMustReturnSenderError"
+    )
+) {
+    companion object {
+        const val message = "aa14"
+    }
+}
+
+open class InsufficientPrefundError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Smart Account does not have sufficient funds to execute the User Operation.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- the Smart Account does not have sufficient funds to cover the required prefund, or",
+            "- a Paymaster was not provided",
+        ),
+        name = "InsufficientPrefundError"
+    )
+) {
+    companion object {
+        const val message = "aa21"
+    }
+}
+
+open class InternalCallOnlyError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Bundler attempted to call an invalid function on the EntryPoint.",
+    BaseErrorParameters(
+        cause,
+        name = "InternalCallOnlyError"
+    )
+) {
+    companion object {
+        const val message = "aa92"
+    }
+}
+
+open class InvalidAggregatorError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Bundler used an invalid aggregator for handling aggregated User Operations.",
+    BaseErrorParameters(
+        cause,
+        name = "InvalidAggregatorError"
+    )
+) {
+    companion object {
+        const val message = "aa96"
+    }
+}
+
+open class InvalidAccountNonceError(
+    cause: BaseError? = null,
+    nonce: BigInteger? = null,
+) : BaseError(
+    "Invalid Smart Account nonce used for User Operation.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = nonce?.let {
+            mutableListOf("nonce: $it")
+        },
+        name = "InvalidAccountNonceError"
+    )
+) {
+    companion object {
+        const val message = "aa25"
+    }
+}
+
+open class InvalidBeneficiaryError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Bundler has not set a beneficiary address.",
+    BaseErrorParameters(
+        cause,
+        name = "InvalidBeneficiaryError"
+    )
+) {
+    companion object {
+        const val message = "aa90"
+    }
+}
+
+open class InvalidFieldsError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Invalid fields set on User Operation.",
+    BaseErrorParameters(
+        cause,
+        name = "InvalidFieldsError"
+    )
+) {
+    companion object {
+        const val code: Int = -32602
+    }
+}
+
+open class InvalidPaymasterAndDataError(
+    cause: BaseError? = null,
+    paymasterAndData: String? = null,
+) : BaseError(
+    "Paymaster properties provided are invalid.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- the `paymasterAndData` property is of an incorrect length\n",
+        ).apply {
+            paymasterAndData?.let { add("paymasterAndData: $it") }
+        },
+        name = "InvalidPaymasterAndDataError"
+    )
+) {
+    companion object {
+        const val message = "aa93"
+    }
+}
+
+open class PaymasterDepositTooLowError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Paymaster deposit for the User Operation is too low.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- the Paymaster has deposited less than the expected amount via the `deposit` function",
+        ),
+        name = "PaymasterDepositTooLowError"
+    )
+) {
+    companion object {
+        const val code: Int = -32508
+        const val message = "aa31"
+    }
+
+}
+
+open class PaymasterFunctionRevertedError(
+    cause: BaseError? = null,
+) : BaseError(
+    "The `validatePaymasterUserOp` function on the Paymaster reverted.",
+    BaseErrorParameters(
+        cause,
+        name = "PaymasterFunctionRevertedError"
+    )
+) {
+    companion object {
+        const val message = "aa33"
+    }
+}
+
+open class PaymasterNotDeployedError(
+    cause: BaseError? = null,
+) : BaseError(
+    "The Paymaster contract has not been deployed.",
+    BaseErrorParameters(
+        cause,
+        name = "PaymasterNotDeployedError"
+    )
+) {
+    companion object {
+        const val message = "aa30"
+    }
+}
+
+open class PaymasterRateLimitError(
+    cause: BaseError? = null,
+) : BaseError(
+    "UserOperation rejected because paymaster (or signature aggregator) is throttled/banned.",
+    BaseErrorParameters(
+        cause,
+        name = "PaymasterRateLimitError"
+    )
+) {
+    companion object {
+        const val code: Int = -32504
+    }
+}
+
+open class PaymasterStakeTooLowError(
+    cause: BaseError? = null,
+) : BaseError(
+    "UserOperation rejected because paymaster (or signature aggregator) is throttled/banned.",
+    BaseErrorParameters(
+        cause,
+        name = "PaymasterStakeTooLowError"
+    )
+) {
+    companion object {
+        const val code: Int = -32505
+    }
+}
+
+open class PaymasterPostOpFunctionRevertedError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Paymaster `postOp` function reverted.",
+    BaseErrorParameters(
+        cause,
+        name = "PaymasterPostOpFunctionRevertedError"
+    )
+) {
+    companion object {
+        const val message = "aa50"
+    }
+}
+
+open class SenderAlreadyConstructedError(
+    cause: BaseError? = null,
+    factory: String? = null,
+    factoryData: String? = null,
+    initCode: String? = null,
+) : BaseError(
+    "Smart Account has already been deployed.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "Remove the following properties and try again:",
+        ).apply {
+            factory?.let { add("`factory`") }
+            factoryData?.let { add("`factoryData`") }
+            initCode?.let { add("`initCode`") }
+        },
+        name = "SenderAlreadyConstructedError"
+    )
+) {
+    companion object {
+        const val message = "aa10"
+    }
+}
+
+open class SignatureCheckFailedError(
+    cause: BaseError? = null,
+) : BaseError(
+    "UserOperation rejected because account signature check failed (or paymaster signature, if the paymaster uses its data as signature).",
+    BaseErrorParameters(
+        cause,
+        name = "SignatureCheckFailedError"
+    )
+) {
+    companion object {
+        const val code: Int = -32507
+    }
+}
+
+open class SmartAccountFunctionRevertedError(
+    cause: BaseError? = null,
+) : BaseError(
+    "The `validateUserOp` function on the Smart Account reverted.",
+    BaseErrorParameters(
+        cause,
+        name = "SmartAccountFunctionRevertedError"
+    )
+) {
+    companion object {
+        const val message = "aa23"
+    }
+}
+
+open class UnsupportedSignatureAggregatorError(
+    cause: BaseError? = null,
+) : BaseError(
+    "UserOperation rejected because account specified unsupported signature aggregator.",
+    BaseErrorParameters(
+        cause,
+        name = "UnsupportedSignatureAggregatorError"
+    )
+) {
+    companion object {
+        const val code: Int = -32506
+    }
+}
+
+open class UserOperationExpiredError(
+    cause: BaseError? = null,
+) : BaseError(
+    "User Operation expired.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- the `validAfter` or `validUntil` values returned from `validateUserOp` on the Smart Account are not satisfied",
+        ),
+        name = "UserOperationExpiredError"
+    )
+) {
+    companion object {
+        const val message = "aa22"
+    }
+}
+
+open class UserOperationPaymasterExpiredError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Paymaster for User Operation expired.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- the `validAfter` or `validUntil` values returned from `validatePaymasterUserOp` on the Paymaster are not satisfied",
+        ),
+        name = "UserOperationPaymasterExpiredError"
+    )
+) {
+    companion object {
+        const val message = "aa32"
+    }
+}
+
+open class UserOperationSignatureError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Signature provided for the User Operation is invalid.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- the `signature` for the User Operation is incorrectly computed, and unable to be verified by the Smart Account",
+        ),
+        name = "UserOperationSignatureError"
+    )
+) {
+    companion object {
+        const val message = "aa24"
+    }
+}
+
+open class UserOperationPaymasterSignatureError(
+    cause: BaseError? = null,
+) : BaseError(
+    "Signature provided for the User Operation is invalid.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- the `signature` for the User Operation is incorrectly computed, and unable to be verified by the Paymaster",
+        ),
+        name = "UserOperationPaymasterSignatureError"
+    )
+) {
+    companion object {
+        const val message = "aa34"
+    }
+}
+
+open class UserOperationRejectedByEntryPointError(
+    cause: BaseError? = null,
+) : BaseError(
+    "User Operation rejected by EntryPoint's `simulateValidation` during account creation or validation.",
+    BaseErrorParameters(
+        cause,
+        name = "UserOperationRejectedByEntryPointError"
+    )
+) {
+    companion object {
+        const val code: Int = -32500
+    }
+}
+
+open class UserOperationRejectedByPaymasterError(
+    cause: BaseError? = null,
+) : BaseError(
+    "User Operation rejected by Paymaster's `validatePaymasterUserOp`.",
+    BaseErrorParameters(
+        cause,
+        name = "UserOperationRejectedByPaymasterError"
+    )
+) {
+    companion object {
+        const val code: Int = -32501
+    }
+}
+
+open class UserOperationRejectedByOpCodeError(
+    cause: BaseError? = null,
+) : BaseError(
+    "User Operation rejected with op code validation error.",
+    BaseErrorParameters(
+        cause,
+        name = "UserOperationRejectedByOpCodeError"
+    )
+) {
+    companion object {
+        const val code: Int = -32502
+    }
+}
+
+open class UserOperationOutOfTimeRangeError(
+    cause: BaseError? = null,
+) : BaseError(
+    "UserOperation out of time-range: either wallet or paymaster returned a time-range, and it is already expired (or will expire soon).",
+    BaseErrorParameters(
+        cause,
+        name = "UserOperationOutOfTimeRangeError"
+    )
+) {
+    companion object {
+        const val code: Int = -32503
+    }
+}
+
+open class UnknownBundlerError(
+    cause: BaseError? = null,
+) : BaseError(
+    "An error occurred while executing user operation: ${cause?.shortMessage}",
+    BaseErrorParameters(
+        cause,
+        name = "UnknownBundlerError"
+    )
+)
+
+open class VerificationGasLimitExceededError(
+    cause: BaseError? = null,
+) : BaseError(
+    "User Operation verification gas limit exceeded.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- the gas used for verification exceeded the `verificationGasLimit`",
+        ),
+        name = "VerificationGasLimitExceededError"
+    )
+) {
+    companion object {
+        const val message = "aa40"
+    }
+}
+
+open class VerificationGasLimitTooLowError(
+    cause: BaseError? = null,
+) : BaseError(
+    "User Operation verification gas limit is too low.",
+    BaseErrorParameters(
+        cause,
+        metaMessages = mutableListOf(
+            "This could arise when:",
+            "- the `verificationGasLimit` is too low to verify the User Operation",
+        ),
+        name = "VerificationGasLimitTooLowError"
+    )
+) {
+    companion object {
+        const val message = "aa41"
+    }
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/errors/EncodingErrors.kt b/lib/src/main/java/com/circle/modularwallets/core/errors/EncodingErrors.kt
new file mode 100644
index 0000000..69e9b20
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/errors/EncodingErrors.kt
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.errors
+
+class IntegerOutOfRangeError(
+    cause: BaseError? = null
+) : BaseError(
+    "The input value is out of range",
+    BaseErrorParameters(
+        cause,
+        name = "IntegerOutOfRangeError"
+    )
+)
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/errors/RequestErrors.kt b/lib/src/main/java/com/circle/modularwallets/core/errors/RequestErrors.kt
new file mode 100644
index 0000000..67633cb
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/errors/RequestErrors.kt
@@ -0,0 +1,82 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.errors
+
+import com.circle.modularwallets.core.transports.JsonRpcError
+import com.circle.modularwallets.core.utils.toJson
+
+
+open class RpcRequestError(
+    body: Any,
+    error: JsonRpcError,
+    url: String
+) : BaseError(
+    "RPC Request failed.",
+    BaseErrorParameters(
+        details = error.message,
+        metaMessages = mutableListOf("URL: $url", "Request body: ${toJson(body)}"),
+        name = "RpcRequestError"
+    )
+) {
+    val code: Int = error.code
+}
+
+open class HttpRequestError(
+    val body: Any? = null,
+    cause: Throwable? = null,
+    details: String? = null,
+    val headers: Any? = null,
+    val status: Int? = null,
+    val url: String
+) : BaseError(
+    "HTTP request failed.",
+    BaseErrorParameters(
+        cause,
+        details,
+        metaMessages = getMetaMessage(status, url, body),
+        name = "HttpRequestError"
+    )
+) {
+    companion object {
+        fun getMetaMessage(status: Int?, url: String, body: Any?): MutableList<String> {
+            val result = mutableListOf<String>()
+            status?.let {
+                result.add("Status: $it")
+            }
+            result.add("URL: $url")
+            body?.let {
+                result.add("Request body: ${toJson(it)}")
+            }
+            return result
+        }
+    }
+}
+
+open class TimeoutError(
+    body: Any?,
+    url: String
+) : BaseError(
+    "The request took too long to respond.",
+    BaseErrorParameters(
+        details = "The request timed out.",
+        metaMessages = mutableListOf("URL: $url", "Request body: ${toJson(body)}"),
+        name = "TimeoutError"
+    )
+)
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/errors/RpcErrors.kt b/lib/src/main/java/com/circle/modularwallets/core/errors/RpcErrors.kt
new file mode 100644
index 0000000..996a570
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/errors/RpcErrors.kt
@@ -0,0 +1,312 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.errors
+
+
+data class RpcErrorOptions(
+    val code: Int? = null,
+    val metaMessages: MutableList<String>? = null,
+    val name: String? = null,
+    val shortMessage: String,
+)
+
+open class RpcError(
+    cause: Throwable,
+    options: RpcErrorOptions,
+) : BaseError(
+    options.shortMessage, BaseErrorParameters(
+        cause,
+        metaMessages = getMetaMessage(options, cause),
+        name = getName(options, cause)
+    )
+) {
+    val code: Int = if (cause is RpcRequestError) {
+        cause.code
+    } else {
+        options.code ?: UnknownRpcError.code
+    }
+
+    companion object {
+        fun getMetaMessage(options: RpcErrorOptions, cause: Throwable): MutableList<String>? {
+            options.metaMessages?.let {
+                return it
+            }
+            if (cause is BaseError) {
+                return cause.metaMessages
+            }
+            return null
+        }
+
+        fun getName(options: RpcErrorOptions, cause: Throwable): String {
+            options.name?.let {
+                return it
+            }
+            if (cause is BaseError) {
+                return cause.name
+            }
+            return "RpcError"
+        }
+    }
+}
+
+open class ProviderRpcError(cause: Throwable, options: RpcErrorOptions) : RpcError(
+    cause,
+    options
+)
+
+class ParseRpcError(cause: Throwable) : RpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "ParseRpcError",
+        shortMessage = "Invalid JSON was received by the server. An error occurred on the server while parsing the JSON text."
+    )
+) {
+    companion object {
+        const val code = -32700
+    }
+}
+
+class InvalidRequestRpcError(cause: Throwable) : RpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "InvalidRequestRpcError",
+        shortMessage = "JSON is not a valid request object."
+    )
+) {
+    companion object {
+        const val code = -32600
+    }
+}
+
+class MethodNotFoundRpcError(cause: Throwable, method: String? = null) : RpcError(
+    cause,
+    RpcErrorOptions(code,
+        name = "MethodNotFoundRpcError",
+        shortMessage = "The method${method?.let { " \"$it\"" } ?: ""} does not exist / is not available.")
+) {
+    companion object {
+        const val code = -32601
+    }
+}
+
+class InvalidParamsRpcError(cause: Throwable) : RpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "InvalidParamsRpcError",
+        shortMessage = "Invalid parameters were provided to the RPC method.\nDouble check you have provided the correct parameters."
+    )
+) {
+    companion object {
+        const val code = -32602
+    }
+}
+
+class InternalRpcError(cause: Throwable) : RpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "InternalRpcError",
+        shortMessage = "An internal error was received."
+    )
+) {
+    companion object {
+        const val code = -32603
+    }
+}
+
+class InvalidInputRpcError(cause: Throwable) : RpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "InvalidInputRpcError",
+        shortMessage = "Missing or invalid parameters.\nDouble check you have provided the correct parameters."
+    )
+) {
+    companion object {
+        const val code = -32000
+    }
+}
+
+class ResourceNotFoundRpcError(cause: Throwable) : RpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "ResourceNotFoundRpcError",
+        shortMessage = "Requested resource not found."
+    )
+) {
+    companion object {
+        const val code = -32001
+    }
+}
+
+class ResourceUnavailableRpcError(cause: Throwable) : RpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "ResourceUnavailableRpcError",
+        shortMessage = "Requested resource not available."
+    )
+) {
+    companion object {
+        const val code = -32002
+    }
+}
+
+class TransactionRejectedRpcError(cause: Throwable) : RpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "TransactionRejectedRpcError",
+        shortMessage = "Transaction creation failed."
+    )
+) {
+    companion object {
+        const val code = -32003
+    }
+}
+
+class MethodNotSupportedRpcError(cause: Throwable, method: String? = null) : RpcError(
+    cause,
+    RpcErrorOptions(code,
+        name = "MethodNotSupportedRpcError",
+        shortMessage = "Method${method?.let { " \"$it\"" } ?: ""} is not implemented.")
+) {
+    companion object {
+        const val code = -32004
+    }
+}
+
+class LimitExceededRpcError(cause: Throwable) : RpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "LimitExceededRpcError",
+        shortMessage = "Request exceeds defined limit."
+    )
+) {
+    companion object {
+        const val code = -32005
+    }
+}
+
+class JsonRpcVersionUnsupportedError(cause: Throwable) : RpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "JsonRpcVersionUnsupportedError",
+        shortMessage = "Version of JSON-RPC protocol is not supported."
+    )
+) {
+    companion object {
+        const val code = -32006
+    }
+}
+
+class UserRejectedRequestError(cause: Throwable) : ProviderRpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "UserRejectedRequestError",
+        shortMessage = "User rejected the request."
+    )
+) {
+    companion object {
+        const val code = 4001
+    }
+}
+
+class UnauthorizedProviderError(cause: Throwable) : ProviderRpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "UnauthorizedProviderError",
+        shortMessage = "The requested method and/or account has not been authorized by the user."
+    )
+) {
+    companion object {
+        const val code = 4100
+    }
+}
+
+class UnsupportedProviderMethodError(cause: Throwable, method: String? = null) : ProviderRpcError(
+    cause,
+    RpcErrorOptions(code,
+        name = "UnsupportedProviderMethodError",
+        shortMessage = "The Provider does not support the requested method${method?.let { " \"$it\"" } ?: ""}.")
+) {
+    companion object {
+        const val code = 4200
+    }
+}
+
+class ProviderDisconnectedError(cause: Throwable) : ProviderRpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "ProviderDisconnectedError",
+        shortMessage = "The Provider is disconnected from all chains."
+    )
+) {
+    companion object {
+        const val code = 4900
+    }
+}
+
+class ChainDisconnectedError(cause: Throwable) : ProviderRpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "ChainDisconnectedError",
+        shortMessage = "The Provider is not connected to the requested chain."
+    )
+) {
+    companion object {
+        const val code = 4901
+    }
+}
+
+class SwitchChainError(cause: Throwable) : ProviderRpcError(
+    cause,
+    RpcErrorOptions(
+        code,
+        name = "SwitchChainError",
+        shortMessage = "An error occurred when attempting to switch chain."
+    )
+) {
+    companion object {
+        const val code = 4902
+    }
+}
+
+class UnknownRpcError(cause: Throwable) : RpcError(
+    cause,
+    RpcErrorOptions(
+        name = "UnknownRpcError",
+        shortMessage = "An unknown RPC error occurred."
+    )
+) {
+    companion object {
+        const val code = -1
+    }
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/errors/UserOperationErrors.kt b/lib/src/main/java/com/circle/modularwallets/core/errors/UserOperationErrors.kt
new file mode 100644
index 0000000..cdb9a3f
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/errors/UserOperationErrors.kt
@@ -0,0 +1,91 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.errors
+
+import com.circle.modularwallets.core.models.UserOperation
+import com.circle.modularwallets.core.models.UserOperationV07
+import com.circle.modularwallets.core.utils.prettyPrint
+import com.circle.modularwallets.core.utils.toMap
+import com.circle.modularwallets.core.utils.unit.formatGwei
+import java.math.BigInteger
+
+
+// https://github.com/wevm/viem/blob/3866a6faeb9e64ba3da6063fe78a079ea53c2c5f/src/account-abstraction/errors/userOperation.ts#L104
+class WaitForUserOperationReceiptTimeoutError(hash: String) : BaseError(
+    "Timed out while waiting for User Operation with hash \"$hash\" to be confirmed.",
+    BaseErrorParameters(name = "WaitForUserOperationReceiptTimeoutError")
+)
+
+// https://github.com/wevm/viem/blob/3866a6faeb9e64ba3da6063fe78a079ea53c2c5f/src/account-abstraction/errors/userOperation.ts#L80
+class UserOperationReceiptNotFoundError(hash: String) : BaseError(
+    "User Operation receipt with hash \"$hash\" could not be found. The User Operation may not have been processed yet.",
+    BaseErrorParameters(name = "UserOperationReceiptNotFoundError")
+)
+
+//https://github.com/wevm/viem/blob/f34580367127be8ec02e2f1a9dbf5d81c29e74e8/src/account-abstraction/errors/userOperation.ts#L89C1-L99C1
+class UserOperationNotFoundError(hash: String) : BaseError(
+    "User Operation with hash \"$hash\" could not be found.",
+    BaseErrorParameters(name = "UserOperationNotFoundError")
+)
+
+class UserOperationExecutionError private constructor(
+    cause: BaseError,
+    parameters: BaseErrorParameters
+) : BaseError(cause.shortMessage, parameters) {
+    constructor(cause: BaseError, userOp: UserOperationV07) : this(
+        cause, BaseErrorParameters(
+            cause,
+            metaMessages = getMetaMessages(cause, getUserOpPrettyPrint(userOp)),
+            name = "UserOperationExecutionError"
+        )
+    )
+
+    companion object {
+        inline fun <reified T : UserOperation> getUserOpPrettyPrint(userOp: T): String {
+            val map = userOp.toMap().toMutableMap()
+            map["maxFeePerGas"]?.let {
+                val n: BigInteger? = if (it is BigInteger) it else null
+                map["maxFeePerGas"] = "${formatGwei(n)} gwei"
+            }
+            map["maxPriorityFeePerGas"]?.let {
+                val n: BigInteger? = if (it is BigInteger) it else null
+                map["maxPriorityFeePerGas"] = "${formatGwei(n)} gwei"
+            }
+            return prettyPrint(map)
+        }
+
+        fun getMetaMessages(cause: BaseError, prettyArgs: String): MutableList<String> {
+            val messages = mutableListOf<String>()
+            cause.metaMessages?.let {
+                messages.addAll(it)
+            }
+
+
+            if (messages.isNotEmpty() && !messages.last().endsWith("\n")) {
+                messages[messages.lastIndex] = messages.last() + "\n"
+            }
+
+            messages.add("Request Arguments:")
+            messages.add(prettyArgs)
+
+            return messages.filter { it.isNotBlank() }.toMutableList()
+        }
+    }
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/Block.kt b/lib/src/main/java/com/circle/modularwallets/core/models/Block.kt
new file mode 100644
index 0000000..26eb5e4
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/Block.kt
@@ -0,0 +1,91 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.models
+
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+import java.math.BigInteger
+
+/**
+ * Data class representing a block.
+ *
+ * @property baseFeePerGas Base fee per gas.
+ * @property blobGasUsed Total used blob gas by all transactions in this block.
+ * @property difficulty Difficulty for this block.
+ * @property excessBlobGas Excess blob gas.
+ * @property extraData "Extra data" field of this block.
+ * @property gasLimit Maximum gas allowed in this block.
+ * @property gasUsed Total used gas by all transactions in this block.
+ * @property hash Block hash or `null` if pending.
+ * @property logsBloom Logs bloom filter or `null` if pending.
+ * @property miner Address that received this block’s mining rewards.
+ * @property mixHash Unique identifier for the block.
+ * @property nonce Proof-of-work hash or `null` if pending.
+ * @property number Block number or `null` if pending.
+ * @property parentBeaconBlockRoot Root of the parent beacon chain block.
+ * @property parentHash Parent block hash.
+ * @property receiptsRoot Root of this block’s receipts trie.
+ * @property sealFields List of seal fields.
+ * @property sha3Uncles SHA3 of the uncles data in this block.
+ * @property size Size of this block in bytes.
+ * @property stateRoot Root of this block’s final state trie.
+ * @property timestamp Unix timestamp of when this block was collated.
+ * @property totalDifficulty Total difficulty of the chain until this block.
+ * @property transactions List of transaction objects or hashes.
+ * @property transactionsRoot Root of this block’s transaction trie.
+ * @property uncles List of uncle hashes.
+ * @property withdrawals List of withdrawal objects.
+ * @property withdrawalsRoot Root of this block’s withdrawals trie.
+ */
+@JsonClass(generateAdapter = true)
+data class Block @JvmOverloads constructor(
+    @Json(name = "baseFeePerGas") var baseFeePerGas: BigInteger? = null,
+    @Json(name = "blobGasUsed") var blobGasUsed: BigInteger? = null,
+    @Json(name = "difficulty") var difficulty: BigInteger? = null,
+    @Json(name = "excessBlobGas") var excessBlobGas: BigInteger? = null,
+    @Json(name = "extraData") var extraData: String? = null,
+    @Json(name = "gasLimit") var gasLimit: BigInteger? = null,
+    @Json(name = "gasUsed") var gasUsed: BigInteger? = null,
+    @Json(name = "hash") var hash: String? = null,
+    @Json(name = "logsBloom") var logsBloom: String? = null,
+    @Json(name = "miner") var miner: String? = null,
+    @Json(name = "mixHash") var mixHash: String? = null,
+    @Json(name = "nonce") var nonce: String? = null,
+    @Json(name = "number") var number: BigInteger? = null,
+    @Json(name = "parentBeaconBlockRoot") var parentBeaconBlockRoot: String? = null,
+    @Json(name = "parentHash") var parentHash: String? = null,
+    @Json(name = "receiptsRoot") var receiptsRoot: String? = null,
+    @Json(name = "sha3Uncles") var sha3Uncles: String? = null,
+    @Json(name = "size") var size: BigInteger? = null,
+    @Json(name = "stateRoot") var stateRoot: String? = null,
+    @Json(name = "timestamp") var timestamp: BigInteger? = null,
+    @Json(name = "totalDifficulty") var totalDifficulty: BigInteger? = null,
+    @Json(name = "transactions") var transactions: Array<String>? = null,
+    @Json(name = "transactionsRoot") var transactionsRoot: String? = null,
+    @Json(name = "uncles") var uncles: Array<String>? = null,
+    @Json(name = "withdrawals") var withdrawals: Array<Withdrawal>? = null,
+    @Json(name = "withdrawalsRoot") var withdrawalsRoot: String? = null,
+)
+
+data class Withdrawal @JvmOverloads constructor(
+    @Json(name = "index") var index: String? = null,
+    @Json(name = "validatorIndex") var validatorIndex: String? = null,
+    @Json(name = "address") var address: String? = null,
+    @Json(name = "amount") var amount: String? = null,
+)
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/BundlerResults.kt b/lib/src/main/java/com/circle/modularwallets/core/models/BundlerResults.kt
new file mode 100644
index 0000000..5d0c989
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/BundlerResults.kt
@@ -0,0 +1,167 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.models
+
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+import java.math.BigInteger
+
+/**
+ * Response model for estimating gas usage for user operations.
+ *
+ * @property preVerificationGas Gas overhead of this UserOperation.
+ * @property verificationGasLimit Estimation of gas limit required by the validation of this UserOperation.
+ * @property callGasLimit Estimation of gas limit required by the inner account execution.
+ * @property paymasterVerificationGasLimit Estimation of gas limit required by the paymaster verification, if the UserOperation defines a Paymaster address.
+ * @property paymasterPostOpGasLimit The amount of gas to allocate for the paymaster post-operation code.
+ */
+@JsonClass(generateAdapter = true)
+data class EstimateUserOperationGasResult @JvmOverloads constructor(
+    @Json(name = "preVerificationGas") var preVerificationGas: BigInteger? = null,
+    @Json(name = "verificationGasLimit") var verificationGasLimit: BigInteger? = null,
+    @Json(name = "callGasLimit") var callGasLimit: BigInteger? = null,
+    @Json(name = "paymasterVerificationGasLimit") var paymasterVerificationGasLimit: BigInteger? = null,
+    @Json(name = "paymasterPostOpGasLimit") var paymasterPostOpGasLimit: BigInteger? = null,
+)
+
+/**
+ * Response model for estimating fees per gas.
+ *
+ * @property maxFeePerGas Total fee per gas in wei (gasPrice/baseFeePerGas + maxPriorityFeePerGas).
+ * @property maxPriorityFeePerGas Max priority fee per gas (in wei).
+ * @property gasPrice Legacy gas price (optional, usually undefined for EIP-1559).
+ */
+@JsonClass(generateAdapter = true)
+data class EstimateFeesPerGasResult @JvmOverloads constructor(
+    val maxFeePerGas: BigInteger? = null,
+    val maxPriorityFeePerGas: BigInteger? = null,
+    val gasPrice: BigInteger? = null,
+)
+
+/**
+ * Response model for getting user operation details.
+ *
+ * @property blockHash The block hash the User Operation was included on.
+ * @property blockNumber The block number the User Operation was included on.
+ * @property entryPoint The EntryPoint which handled the User Operation.
+ * @property transactionHash The hash of the transaction which included the User Operation.
+ * @property userOperation The User Operation.
+ */
+data class GetUserOperationResult(
+    val blockHash: String?,
+    val blockNumber: BigInteger?,
+    val transactionHash: String?,
+    val entryPoint: String?,
+    val userOperation: UserOperationRpc?
+)
+
+/**
+ * Data class representing the receipt of a user operation.
+ *
+ * @property actualGasCost Actual gas cost.
+ * @property actualGasUsed Actual gas used.
+ * @property entryPoint Entrypoint address.
+ * @property logs Logs emitted during execution.
+ * @property nonce Anti-replay parameter.
+ * @property paymaster Paymaster for the user operation.
+ * @property reason Revert reason, if unsuccessful.
+ * @property receipt Transaction receipt of the user operation execution.
+ * @property sender Address of the sender.
+ * @property success If the user operation execution was successful.
+ * @property userOpHash Hash of the user operation.
+ */
+data class UserOperationReceipt(
+    val actualGasCost: BigInteger?,
+    val actualGasUsed: BigInteger?,
+    val entryPoint: String?,
+    val logs: List<Log>?,
+    val nonce: BigInteger?,
+    val paymaster: String?,
+    val reason: String?,
+    val receipt: TransactionReceipt,
+    val sender: String?,
+    val success: Boolean?,
+    val userOpHash: String?,
+)
+
+/**
+ * Data class representing a log entry.
+ *
+ * @property address The address from which this log originated.
+ * @property blockHash Hash of the block containing this log or `null` if pending.
+ * @property blockNumber Number of the block containing this log or `null` if pending.
+ * @property data Contains the non-indexed arguments of the log.
+ * @property logIndex Index of this log within its block or `null` if pending.
+ * @property transactionHash Hash of the transaction that created this log or `null` if pending.
+ * @property transactionIndex Index of the transaction that created this log or `null` if pending.
+ * @property removed `true` if this filter has been destroyed and is invalid.
+ * @property topics List of topics associated with this log.
+ */
+data class Log(
+    val address: String?,
+    val blockHash: String?,
+    val blockNumber: BigInteger?,
+    val data: String?,
+    val logIndex: BigInteger?,
+    val transactionHash: String?,
+    val transactionIndex: BigInteger?,
+    val removed: Boolean?,
+    val topics: List<String>?,
+)
+
+/**
+ * Data class representing the receipt of a transaction.
+ *
+ * @property blobGasPrice The actual value per gas deducted from the sender's account for blob gas. Only specified for blob transactions as defined by EIP-4844.
+ * @property blobGasUsed The amount of blob gas used. Only specified for blob transactions as defined by EIP-4844.
+ * @property blockHash Hash of the block containing this transaction.
+ * @property blockNumber Number of the block containing this transaction.
+ * @property contractAddress Address of the new contract or `null` if no contract was created.
+ * @property cumulativeGasUsed Gas used by this and all preceding transactions in this block.
+ * @property effectiveGasPrice Pre-London, it is equal to the transaction's gasPrice. Post-London, it is equal to the actual gas price paid for inclusion.
+ * @property from Transaction sender.
+ * @property gasUsed Gas used by this transaction.
+ * @property logs List of log objects generated by this transaction.
+ * @property logsBloom Logs bloom filter.
+ * @property root The post-transaction state root. Only specified for transactions included before the Byzantium upgrade.
+ * @property status `success` if this transaction was successful or `reverted` if it failed.
+ * @property to Transaction recipient or `null` if deploying a contract.
+ * @property transactionHash Hash of this transaction.
+ * @property transactionIndex Index of this transaction in the block.
+ * @property type Transaction type.
+ */
+data class TransactionReceipt(
+    val blobGasPrice: BigInteger?,
+    val blobGasUsed: BigInteger?,
+    val blockHash: String?,
+    val blockNumber: BigInteger?,
+    val contractAddress: String?,
+    val cumulativeGasUsed: BigInteger?,
+    val effectiveGasPrice: BigInteger?,
+    val from: String?,
+    val gasUsed: BigInteger?,
+    val logs: List<Log>?,
+    val logsBloom: String?,
+    val root: String?,
+    val status: String?,
+    val to: String?,
+    val transactionHash: String?,
+    val transactionIndex: BigInteger?,
+    val type: String?,
+)
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/EIP712TypedData.kt b/lib/src/main/java/com/circle/modularwallets/core/models/EIP712TypedData.kt
new file mode 100644
index 0000000..470b628
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/EIP712TypedData.kt
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.models
+
+import com.circle.modularwallets.core.constants.REPLAY_SAFE_HASH_V1
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+
+@JsonClass(generateAdapter = true)
+data class EIP712Message @JvmOverloads constructor(
+    @Json(name = "types") var types: MutableMap<String, MutableList<Entry>>? = null,
+    @Json(name = "primaryType") var primaryType: String? = null,
+    @Json(name = "message") var message: MutableMap<String, Any>? = null,
+    @Json(name = "domain") var domain: EIP712Domain? = null,
+)
+
+@JsonClass(generateAdapter = true)
+data class Entry @JvmOverloads constructor(
+    @Json(name = "name") var name: String? = null,
+    @Json(name = "type") var type: String? = null,
+)
+
+@JsonClass(generateAdapter = true)
+data class EIP712Domain @JvmOverloads constructor(
+    @Json(name = "name") var name: String? = null,
+    @Json(name = "version") var version: String? = null,
+    @Json(name = "chainId") var chainId: Long? = null,
+    @Json(name = "verifyingContract") val verifyingContract: String? = null,
+    @Json(name = "salt") var salt: String? = null,
+)
+
+internal fun getCircleDomainMessage(chainId: Long, verifyingContract: String, hash: String): EIP712Message {
+    return EIP712Message(
+        domain = EIP712Domain(
+            REPLAY_SAFE_HASH_V1.name,
+            REPLAY_SAFE_HASH_V1.version,
+            chainId,
+            verifyingContract
+        ),
+        types = mutableMapOf(
+            REPLAY_SAFE_HASH_V1.primaryType to mutableListOf(
+                Entry(
+                    "hash",
+                    "bytes32"
+                )
+            )
+        ),
+        primaryType = REPLAY_SAFE_HASH_V1.primaryType,
+        message = mutableMapOf("hash" to hash)
+    )
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/EncodeCallDataArg.kt b/lib/src/main/java/com/circle/modularwallets/core/models/EncodeCallDataArg.kt
new file mode 100644
index 0000000..9a6e629
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/EncodeCallDataArg.kt
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.circle.modularwallets.core.models
+
+import com.circle.modularwallets.core.utils.abi.encodeFunctionData
+import java.math.BigInteger
+
+/**
+ * Data class representing arguments required for encoding call data.
+ *
+ * @property to The recipient address.
+ * @property value The value to be sent with the transaction.
+ * @property data The call data in hexadecimal format.
+ * @property abiJson The ABI definition in JSON format.
+ * @property args The arguments for the function call.
+ * @property functionName The function name.
+ */
+data class EncodeCallDataArg @JvmOverloads constructor(
+    val to: String,
+    val value: BigInteger? = null,
+    val data: String? = null, //hex
+    val abiJson: String? = null,
+    val args: Array<Any>? = null,
+    val functionName: String? = null
+) {
+    internal fun dataUpdated(): EncodeCallDataArg {
+        if (!abiJson.isNullOrBlank() && !functionName.isNullOrBlank()) {
+            return EncodeCallDataArg(
+                to,
+                value,
+                encodeFunctionData(
+                    functionName,
+                    abiJson,
+                    args ?: emptyArray()
+                )
+            )
+        }
+        return this
+    }
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/EncodeTransferResult.kt b/lib/src/main/java/com/circle/modularwallets/core/models/EncodeTransferResult.kt
new file mode 100644
index 0000000..8fce370
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/EncodeTransferResult.kt
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.models
+
+/**
+ * The return type for encodeTransfer.
+ */
+data class EncodeTransferResult(
+    /**
+     * The encoded data.
+     */
+    val data: String,
+    /**
+     * The token address.
+     */
+    val to: String
+)
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/EntryPoint.kt b/lib/src/main/java/com/circle/modularwallets/core/models/EntryPoint.kt
new file mode 100644
index 0000000..38ed51a
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/EntryPoint.kt
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.models
+
+interface IEntryPoint {
+    val address: String
+}
+
+/**
+ * Enum class representing entry points with their respective addresses.
+ *
+ * @property address The address of the entry point.
+ */
+enum class EntryPoint(override val address: String) :IEntryPoint{
+    /**
+     * Represents the entry point version 0.7 with its respective address.
+     */
+    V07("0x0000000071727De22E5E9d8BAf0edAc6f37da032");
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/Paymaster.kt b/lib/src/main/java/com/circle/modularwallets/core/models/Paymaster.kt
new file mode 100644
index 0000000..339632f
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/Paymaster.kt
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.models
+
+import com.circle.modularwallets.core.clients.PaymasterClient
+
+/**
+ * Sealed class for setting User Operation Paymaster configuration.
+ *
+ * If `paymaster` is `PaymasterClient`, it will use the provided Paymaster Client for sponsorship.
+ * If `paymaster` is `true`, it will be assumed that the Bundler Client also supports Paymaster RPC methods
+ * (e.g. `pm_getPaymasterData`), and use them for sponsorship.
+ */
+sealed class Paymaster {
+    /**
+     * Represents a Paymaster configuration where the Bundler Client supports Paymaster RPC methods.
+     *
+     * @property paymasterContext Optional context for the paymaster.
+     */
+    data class True @JvmOverloads constructor(
+        val paymasterContext: Map<String, Any>? = null
+    ) : Paymaster()
+
+    /**
+     * Represents a Paymaster configuration using a provided Paymaster Client for sponsorship.
+     *
+     * @property client The Paymaster Client used for sponsorship.
+     * @property paymasterContext Optional context for the paymaster.
+     */
+    data class Client @JvmOverloads constructor(
+        val client: PaymasterClient,
+        val paymasterContext: Map<String, Any>? = null
+    ) : Paymaster()
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/PaymasterResults.kt b/lib/src/main/java/com/circle/modularwallets/core/models/PaymasterResults.kt
new file mode 100644
index 0000000..a9e6b95
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/PaymasterResults.kt
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.models
+
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+import java.math.BigInteger
+
+/**
+ * Data class representing the result of getting paymaster data.
+ *
+ * @property paymasterAndData Combined paymaster and data.
+ * @property paymasterData Paymaster data.
+ * @property paymaster Paymaster address.
+ * @property paymasterPostOpGasLimit Gas limit for post-operation of paymaster.
+ * @property paymasterVerificationGasLimit Gas limit for verification of paymaster.
+ */
+@JsonClass(generateAdapter = true)
+data class GetPaymasterDataResult @JvmOverloads constructor(
+    @Json(name = "paymasterAndData") var paymasterAndData: String? = null,
+    @Json(name = "paymasterData") var paymasterData: String? = null,
+    @Json(name = "paymaster") var paymaster: String? = null,
+    @Json(name = "paymasterPostOpGasLimit") var paymasterPostOpGasLimit: BigInteger? = null,
+    @Json(name = "paymasterVerificationGasLimit") var paymasterVerificationGasLimit: BigInteger? = null,
+)
+
+/**
+ * Data class representing the result of getting paymaster stub data.
+ *
+ * @property paymasterAndData Combined paymaster and data.
+ * @property paymaster Paymaster address.
+ * @property paymasterData Paymaster data.
+ * @property paymasterPostOpGasLimit Gas limit for post-operation of paymaster.
+ * @property paymasterVerificationGasLimit Gas limit for verification of paymaster.
+ * @property isFinal Indicates if the data is final.
+ * @property sponsor Sponsor information.
+ */
+@JsonClass(generateAdapter = true)
+data class GetPaymasterStubDataResult @JvmOverloads constructor(
+    @Json(name = "paymasterAndData") var paymasterAndData: String? = null,
+    @Json(name = "paymaster") var paymaster: String? = null,
+    @Json(name = "paymasterData") var paymasterData: String? = null,
+    @Json(name = "paymasterPostOpGasLimit") var paymasterPostOpGasLimit: BigInteger? = null,
+    @Json(name = "paymasterVerificationGasLimit") var paymasterVerificationGasLimit: BigInteger? = null,
+    @Json(name = "isFinal") var isFinal: Boolean? = null,
+    @Json(name = "sponsor") var sponsor: Sponsor? = null,
+)
+/**
+ * Data class representing sponsor information.
+ *
+ * @property name Sponsor name.
+ * @property icon Sponsor icon.
+ */
+@JsonClass(generateAdapter = true)
+data class Sponsor @JvmOverloads constructor(
+    var name: String? = null,
+    var icon: String? = null
+)
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/PublicKeyCredentials.kt b/lib/src/main/java/com/circle/modularwallets/core/models/PublicKeyCredentials.kt
new file mode 100644
index 0000000..6a36079
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/PublicKeyCredentials.kt
@@ -0,0 +1,145 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.models
+
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+
+/**
+ * Abstract class representing a public key credential.
+ *
+ * @property id The unique identifier for the credential.
+ * @property type The type of the credential.
+ * @property authenticatorAttachment The attachment type of the authenticator.
+ * @property response The response from the authenticator.
+ * @property clientExtensionResults Optional client extension results.
+ */
+abstract class PublicKeyCredential {
+    abstract val id: String
+    abstract val type: String
+    abstract val authenticatorAttachment: String
+    abstract val response: AuthenticatorResponse
+    abstract val clientExtensionResults: AuthenticationExtensionsClientOutputs?
+}
+
+/**
+ * Abstract class representing a response from an authenticator.
+ *
+ * @property clientDataJSON The client data in JSON format.
+ */
+abstract class AuthenticatorResponse {
+    abstract val clientDataJSON: String
+}
+
+/**
+ * Data class representing a registration credential.
+ *
+ * @property rawId The raw identifier for the credential.
+ * @property authenticatorAttachment The attachment type of the authenticator.
+ * @property type The type of the credential.
+ * @property id The unique identifier for the credential.
+ * @property response The attestation response from the authenticator.
+ * @property clientExtensionResults Optional client extension results.
+ */
+@JsonClass(generateAdapter = true)
+data class RegistrationCredential(
+    @Json(name = "rawId") val rawId: String,
+    @Json(name = "authenticatorAttachment") override val authenticatorAttachment: String,
+    @Json(name = "type") override val type: String,
+    @Json(name = "id") override val id: String,
+    @Json(name = "response") override val response: AuthenticatorAttestationResponse,
+    @Json(name = "clientExtensionResults") override val clientExtensionResults: AuthenticationExtensionsClientOutputs?,
+) : PublicKeyCredential()
+
+/**
+ * Data class representing an attestation response from an authenticator.
+ *
+ * @property clientDataJSON The client data in JSON format.
+ * @property attestationObject The attestation object.
+ * @property transports The list of supported transports.
+ * @property authenticatorData The authenticator data.
+ * @property publicKeyAlgorithm The public key algorithm.
+ * @property publicKey The public key.
+ */
+@JsonClass(generateAdapter = true)
+data class AuthenticatorAttestationResponse(
+    @Json(name = "clientDataJSON") override val clientDataJSON: String,
+    @Json(name = "attestationObject") val attestationObject: String,
+    @Json(name = "transports") val transports: List<String>,
+    @Json(name = "authenticatorData") val authenticatorData: String,
+    @Json(name = "publicKeyAlgorithm") val publicKeyAlgorithm: Int,
+    @Json(name = "publicKey") val publicKey: String,
+) : AuthenticatorResponse()
+
+/**
+ * Data class representing an authentication credential.
+ *
+ * @property rawId The raw identifier for the credential.
+ * @property authenticatorAttachment The attachment type of the authenticator.
+ * @property type The type of the credential.
+ * @property id The unique identifier for the credential.
+ * @property response The assertion response from the authenticator.
+ * @property clientExtensionResults Optional client extension results.
+ */
+@JsonClass(generateAdapter = true)
+data class AuthenticationCredential(
+    @Json(name = "rawId") val rawId: String,
+    @Json(name = "authenticatorAttachment") override val authenticatorAttachment: String,
+    @Json(name = "type") override val type: String,
+    @Json(name = "id") override val id: String,
+    @Json(name = "response") override val response: AuthenticatorAssertionResponse,
+    @Json(name = "clientExtensionResults") override val clientExtensionResults: AuthenticationExtensionsClientOutputs?,
+) : PublicKeyCredential()
+
+/**
+ * Data class representing an assertion response from an authenticator.
+ *
+ * @property clientDataJSON The client data in JSON format.
+ * @property authenticatorData The authenticator data.
+ * @property signature The signature.
+ * @property userHandle The user handle.
+ */
+@JsonClass(generateAdapter = true)
+data class AuthenticatorAssertionResponse(
+    @Json(name = "clientDataJSON") override val clientDataJSON: String,
+    @Json(name = "authenticatorData") val authenticatorData: String,
+    @Json(name = "signature") val signature: String,
+    @Json(name = "userHandle") val userHandle: String,
+) : AuthenticatorResponse()
+
+/**
+ * Data class representing client extension outputs for authentication.
+ *
+ * @property credProps Optional credential properties output.
+ */
+@JsonClass(generateAdapter = true)
+data class AuthenticationExtensionsClientOutputs @JvmOverloads constructor(
+    @Json(name = "credProps") val credProps: CredentialPropertiesOutput? = null,
+)
+
+/**
+ * Data class representing credential properties output.
+ *
+ * @property rk Optional resident key property.
+ */
+@JsonClass(generateAdapter = true)
+data class CredentialPropertiesOutput(
+    @Json(name = "rk") val rk: Boolean? = null,
+)
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/SignResult.kt b/lib/src/main/java/com/circle/modularwallets/core/models/SignResult.kt
new file mode 100644
index 0000000..3173682
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/SignResult.kt
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.models
+
+import com.circle.modularwallets.core.utils.encoding.bytesToHex
+import com.circle.modularwallets.core.utils.signature.base64DecodeToString
+import com.circle.modularwallets.core.utils.signature.base64UrlToBytes
+
+/**
+ * Data class representing the result of a signing operation.
+ *
+ * @param signature The signature generated by the signing operation.
+ * @param webAuthn The WebAuthn data associated with the signing operation.
+ * @param raw The raw authentication credential used in the signing operation.
+ */
+data class SignResult(
+    val signature: String,
+    val webAuthn: WebAuthnData,
+    val raw: AuthenticationCredential,
+)
+
+/**
+ * Data class representing WebAuthn data.
+ *
+ * @param authenticatorData The authenticator data in hexadecimal format.
+ * @param challengeIndex The index of the challenge in the client data JSON.
+ * @param clientDataJSON The client data JSON.
+ * @param typeIndex The index of the type in the client data JSON.
+ * @param userVerificationRequired Indicates whether user verification is required.
+ */
+data class WebAuthnData(
+    val authenticatorData: String,
+    val challengeIndex: Int,
+    val clientDataJSON: String,
+    val typeIndex: Int,
+    val userVerificationRequired: Boolean,
+)
+
+internal fun AuthenticationCredential.toWebAuthnData(userVerification: String): WebAuthnData {
+    val decoded = base64DecodeToString(response.clientDataJSON)
+
+    return WebAuthnData(
+        bytesToHex(base64UrlToBytes(response.authenticatorData)),
+        decoded.indexOf("\"challenge\""),
+        decoded,
+        decoded.indexOf("\"type\""),
+        userVerification == "required"
+    )
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/Token.kt b/lib/src/main/java/com/circle/modularwallets/core/models/Token.kt
new file mode 100644
index 0000000..f03ea5e
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/Token.kt
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.circle.modularwallets.core.models
+
+import com.circle.modularwallets.core.utils.abi.encodeTransfer
+
+/**
+ * Enum representing various tokens supported by [encodeTransfer].
+ * The format is {chain}_{symbol}
+ */
+enum class Token {
+    Arbitrum_USDC,
+    Arbitrum_ARB,
+    ArbitrumSepolia_USDC,
+    Polygon_USDC,
+    PolygonAmoy_USDC;
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/UserOperation.kt b/lib/src/main/java/com/circle/modularwallets/core/models/UserOperation.kt
new file mode 100644
index 0000000..b138995
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/UserOperation.kt
@@ -0,0 +1,197 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.models
+
+import com.circle.modularwallets.core.utils.encoding.bigIntegerToHex
+import com.circle.modularwallets.core.utils.encoding.hexToBigInteger
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+import java.math.BigInteger
+
+/**
+ * Abstract class representing a user operation.
+ *
+ * @property sender The address of the sender.
+ * @property nonce The nonce of the operation.
+ * @property callData The data to be sent in the call.
+ * @property callGasLimit The gas limit for the call.
+ * @property verificationGasLimit The gas limit for verification.
+ * @property preVerificationGas The gas used before verification.
+ * @property maxPriorityFeePerGas The maximum priority fee per gas.
+ * @property maxFeePerGas The maximum fee per gas.
+ * @property signature The signature of the operation.
+ */
+abstract class UserOperation {
+    abstract var sender: String?
+    abstract var nonce: BigInteger?
+    abstract var callData: String?
+    abstract var callGasLimit: BigInteger?
+    abstract var verificationGasLimit: BigInteger?
+    abstract var preVerificationGas: BigInteger?
+    abstract var maxPriorityFeePerGas: BigInteger?
+    abstract var maxFeePerGas: BigInteger?
+    abstract var signature: String?
+}
+
+/**
+ * Data class representing a user operation for version 0.7.
+ *
+ * @property sender The address of the sender.
+ * @property nonce The nonce of the operation.
+ * @property callData The data to be sent in the call.
+ * @property callGasLimit The gas limit for the call.
+ * @property verificationGasLimit The gas limit for verification.
+ * @property preVerificationGas The gas used before verification.
+ * @property maxPriorityFeePerGas The maximum priority fee per gas.
+ * @property maxFeePerGas The maximum fee per gas.
+ * @property signature The signature of the operation.
+ * @property factory The factory address.
+ * @property factoryData The data for the factory.
+ * @property paymaster The paymaster address.
+ * @property paymasterVerificationGasLimit The gas limit for paymaster verification.
+ * @property paymasterPostOpGasLimit The gas limit for paymaster post-operation.
+ * @property paymasterData The data for the paymaster.
+ */
+@JsonClass(generateAdapter = true)
+data class UserOperationV07 @JvmOverloads constructor(
+    @Json(name = "sender") override var sender: String? = null,
+    @Json(name = "nonce") override var nonce: BigInteger? = null,
+    @Json(name = "callData") override var callData: String? = null,
+    @Json(name = "callGasLimit") override var callGasLimit: BigInteger? = null,
+    @Json(name = "verificationGasLimit") override var verificationGasLimit: BigInteger? = null,
+    @Json(name = "preVerificationGas") override var preVerificationGas: BigInteger? = null,
+    @Json(name = "maxPriorityFeePerGas") override var maxPriorityFeePerGas: BigInteger? = null,
+    @Json(name = "maxFeePerGas") override var maxFeePerGas: BigInteger? = null,
+    @Json(name = "signature") override var signature: String? = null,
+    @Json(name = "factory") var factory: String? = null,
+    @Json(name = "factoryData") var factoryData: String? = null,
+    @Json(name = "paymaster") var paymaster: String? = null,
+    @Json(name = "paymasterVerificationGasLimit") var paymasterVerificationGasLimit: BigInteger? = null,
+    @Json(name = "paymasterPostOpGasLimit") var paymasterPostOpGasLimit: BigInteger? = null,
+    @Json(name = "paymasterData") var paymasterData: String? = null
+) : UserOperation()
+
+/**
+ * Converts a `UserOperationV07` instance to a `UserOperationRpc` instance.
+ *
+ * @return A `UserOperationRpc` instance with the corresponding properties from the `UserOperationV07` instance.
+ */
+fun UserOperationV07.toRpcUserOperation(): UserOperationRpc {
+    return UserOperationRpc(
+        sender = this.sender,
+        nonce = bigIntegerToHex(this.nonce),
+        callData = this.callData,
+        callGasLimit = bigIntegerToHex(this.callGasLimit),
+        verificationGasLimit = bigIntegerToHex(this.verificationGasLimit),
+        preVerificationGas = bigIntegerToHex(this.preVerificationGas),
+        maxPriorityFeePerGas = bigIntegerToHex(this.maxPriorityFeePerGas),
+        maxFeePerGas = bigIntegerToHex(this.maxFeePerGas),
+        signature = this.signature,
+        factory = this.factory,
+        factoryData = this.factoryData,
+        paymaster = this.paymaster,
+        paymasterData = this.paymasterData,
+        paymasterVerificationGasLimit = bigIntegerToHex(this.paymasterVerificationGasLimit),
+        paymasterPostOpGasLimit = bigIntegerToHex(this.paymasterPostOpGasLimit),
+    )
+}
+
+/**
+ * Converts a `UserOperation` instance to a `UserOperationRpc` instance.
+ *
+ * @return A `UserOperationRpc` instance with the corresponding properties from the `UserOperation` instance.
+ */
+fun UserOperation.toRpcUserOperation(): UserOperationRpc {
+    return UserOperationRpc(
+        sender = this.sender,
+        nonce = bigIntegerToHex(this.nonce),
+        callData = this.callData,
+        callGasLimit = bigIntegerToHex(this.callGasLimit),
+        verificationGasLimit = bigIntegerToHex(this.verificationGasLimit),
+        preVerificationGas = bigIntegerToHex(this.preVerificationGas),
+        maxPriorityFeePerGas = bigIntegerToHex(this.maxPriorityFeePerGas),
+        maxFeePerGas = bigIntegerToHex(this.maxFeePerGas),
+        signature = this.signature
+    )
+}
+
+/**
+ * Converts a `UserOperationRpc` instance to a `UserOperationV07` instance.
+ *
+ * @return A `UserOperationV07` instance with the corresponding properties from the `UserOperationRpc` instance.
+ */
+fun UserOperationRpc.toUserOperationV07(): UserOperationV07 {
+    return UserOperationV07(
+        sender = this.sender,
+        nonce = hexToBigInteger(this.nonce),
+        callData = this.callData,
+        callGasLimit = hexToBigInteger(this.callGasLimit),
+        verificationGasLimit = hexToBigInteger(this.verificationGasLimit),
+        preVerificationGas = hexToBigInteger(this.preVerificationGas),
+        maxPriorityFeePerGas = hexToBigInteger(this.maxPriorityFeePerGas),
+        maxFeePerGas = hexToBigInteger(this.maxFeePerGas),
+        signature = this.signature,
+        factory = this.factory,
+        factoryData = this.factoryData,
+        paymaster = this.paymaster,
+        paymasterVerificationGasLimit = hexToBigInteger(this.paymasterVerificationGasLimit),
+    )
+}
+
+/**
+ * Data class representing a user operation in RPC format.
+ *
+ * @property sender The address of the sender.
+ * @property nonce The nonce of the operation.
+ * @property callData The data to be sent in the call.
+ * @property callGasLimit The gas limit for the call.
+ * @property verificationGasLimit The gas limit for verification.
+ * @property preVerificationGas The gas used before verification.
+ * @property maxPriorityFeePerGas The maximum priority fee per gas.
+ * @property maxFeePerGas The maximum fee per gas.
+ * @property signature The signature of the operation.
+ * @property factory The factory address.
+ * @property factoryData The data for the factory.
+ * @property paymaster The paymaster address.
+ * @property paymasterVerificationGasLimit The gas limit for paymaster verification.
+ * @property paymasterPostOpGasLimit The gas limit for paymaster post-operation.
+ * @property paymasterData The data for the paymaster.
+ * @property initCode The initialization code.
+ * @property paymasterAndData The paymaster and data.
+ */
+@JsonClass(generateAdapter = true)
+data class UserOperationRpc @JvmOverloads constructor(
+    @Json(name = "sender") var sender: String? = null,
+    @Json(name = "nonce") var nonce: String? = null,
+    @Json(name = "callData") var callData: String? = null,
+    @Json(name = "callGasLimit") var callGasLimit: String? = null,
+    @Json(name = "verificationGasLimit") var verificationGasLimit: String? = null,
+    @Json(name = "preVerificationGas") var preVerificationGas: String? = null,
+    @Json(name = "maxPriorityFeePerGas") var maxPriorityFeePerGas: String? = null,
+    @Json(name = "maxFeePerGas") var maxFeePerGas: String? = null,
+    @Json(name = "signature") var signature: String? = null,
+    @Json(name = "factory") var factory: String? = null,
+    @Json(name = "factoryData") var factoryData: String? = null,
+    @Json(name = "paymaster") var paymaster: String? = null,
+    @Json(name = "paymasterVerificationGasLimit") var paymasterVerificationGasLimit: String? = null,
+    @Json(name = "paymasterPostOpGasLimit") var paymasterPostOpGasLimit: String? = null,
+    @Json(name = "paymasterData") var paymasterData: String? = null,
+    @Json(name = "initCode") var initCode: String? = null,
+    @Json(name = "paymasterAndData") var paymasterAndData: String? = null
+)
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/WebAuthnMode.kt b/lib/src/main/java/com/circle/modularwallets/core/models/WebAuthnMode.kt
new file mode 100644
index 0000000..6b721c3
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/WebAuthnMode.kt
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.models
+
+/**
+ * Enum class representing the WebAuthn modes.
+ */
+enum class WebAuthnMode {
+    /**
+     * Mode for registering a new credential.
+     */
+    Register,
+
+    /**
+     * Mode for logging in with an existing credential.
+     */
+    Login
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/transports/JsonRpcReqResp.kt b/lib/src/main/java/com/circle/modularwallets/core/transports/JsonRpcReqResp.kt
new file mode 100644
index 0000000..db49c10
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/transports/JsonRpcReqResp.kt
@@ -0,0 +1,56 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.transports
+
+import androidx.annotation.Keep
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+
+@Keep
+@JsonClass(generateAdapter = true)
+data class RpcRequest @JvmOverloads constructor(
+    @Json(name = "method") val method: String,
+    @Json(name = "params") val params: Any? = null,
+    @Json(name = "id") val id: Long = System.currentTimeMillis(),
+    @Json(name = "jsonrpc") val jsonrpc: String = "2.0",
+)
+
+@Keep
+@JsonClass(generateAdapter = true)
+data class RpcResponse(
+    @Json(name = "id") val id: String,
+    @Json(name = "jsonrpc") val jsonrpc: String,
+    @Json(name = "error") val error: JsonRpcError?,
+    @Json(name = "result") val result: Any?,
+)
+
+@Keep
+@JsonClass(generateAdapter = true)
+data class JsonRpcError(
+    @Json(name = "code") val code: Int,
+    @Json(name = "message") val message: String
+)
+
+@Keep
+@JsonClass(generateAdapter = true)
+data class HttpError(
+    @Json(name = "statusCode") val statusCode: Int? = null,
+    @Json(name = "error") val error: String? = null,
+    @Json(name = "message") val message: String? = null,
+)
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/transports/Transport.kt b/lib/src/main/java/com/circle/modularwallets/core/transports/Transport.kt
new file mode 100644
index 0000000..85731ea
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/transports/Transport.kt
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.transports
+
+import retrofit2.Response
+
+/**
+ * Interface representing a transport mechanism for making RPC requests.
+ */
+interface Transport {
+    /**
+     * Sends an RPC request and returns the response.
+     *
+     * @param req The RPC request to be sent.
+     * @return The response from the RPC request.
+     */
+    suspend fun request(req: RpcRequest): Response<RpcResponse>
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/transports/http/HttpTransport.kt b/lib/src/main/java/com/circle/modularwallets/core/transports/http/HttpTransport.kt
new file mode 100644
index 0000000..e2c27dc
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/transports/http/HttpTransport.kt
@@ -0,0 +1,114 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.circle.modularwallets.core.transports.http
+
+import android.content.Context
+import com.circle.modularwallets.core.transports.RpcRequest
+import com.circle.modularwallets.core.transports.RpcResponse
+import com.circle.modularwallets.core.transports.Transport
+import retrofit2.Response
+import retrofit2.http.Body
+import retrofit2.http.POST
+import retrofit2.http.Url
+
+/**
+ * Data class representing HTTP RPC client options.
+ *
+ * @property headers Optional headers to include in the HTTP requests.
+ */
+data class HttpRpcClientOptions @JvmOverloads constructor(
+    val headers: Map<String, String>? = null
+)
+
+interface HttpTransport : Transport {
+    override suspend fun request(@Body req: RpcRequest): Response<RpcResponse>
+}
+
+internal class HttpTransportImpl(val url: String, private val service: RetrofitService) :
+    HttpTransport {
+    override suspend fun request(req: RpcRequest): Response<RpcResponse> {
+        return service.request(url, req)
+    }
+}
+
+internal interface RetrofitService {
+    @POST
+    suspend fun request(@Url url: String, @Body req: RpcRequest): Response<RpcResponse>
+}
+
+/**
+ * Creates a HTTP transport instance.
+ *
+ * @param context The application context.
+ * @param clientKey The client key for authorization.
+ * @param url The URL for the HTTP transport.
+ * @return The configured HTTP transport instance.
+ */
+fun toModularTransport(
+    context: Context,
+    clientKey: String,
+    url: String
+): HttpTransport {
+    return http(
+        context,
+        url,
+        HttpRpcClientOptions(headers = mapOf("Authorization" to "Bearer $clientKey"))
+    )
+}
+
+/**
+ * Creates a HTTP transport instance.
+ *
+ * @param context The application context.
+ * @param clientKey The client key for authorization.
+ * @param url The URL for the HTTP transport.
+ * @return The configured HTTP transport instance.
+ */
+fun toPasskeyTransport(
+    context: Context,
+    clientKey: String,
+    url: String
+): HttpTransport {
+    return http(
+        context,
+        url,
+        HttpRpcClientOptions(headers = mapOf("Authorization" to "Bearer $clientKey"))
+    )
+}
+
+/**
+ * Creates an HTTP transport instance.
+ *
+ * @param context The application context.
+ * @param url The URL for the HTTP transport.
+ * @param config The configuration options for the HTTP transport (default is an empty configuration).
+ * @return The configured HTTP transport instance.
+ */
+
+@JvmOverloads
+fun http(
+    context: Context,
+    url: String,
+    config: HttpRpcClientOptions = HttpRpcClientOptions()
+): HttpTransport {
+    val transport = RetrofitProvider().get(
+        context,
+        url, config
+    ).create(RetrofitService::class.java)
+    return HttpTransportImpl(url, transport)
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/transports/http/RetrofitProvider.kt b/lib/src/main/java/com/circle/modularwallets/core/transports/http/RetrofitProvider.kt
new file mode 100644
index 0000000..6d1beee
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/transports/http/RetrofitProvider.kt
@@ -0,0 +1,108 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.circle.modularwallets.core.transports.http
+
+import android.content.Context
+import android.text.TextUtils
+import android.util.Log
+import com.circle.modularwallets.core.BuildConfig
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.errors.HttpRequestError
+import com.circle.modularwallets.core.errors.TimeoutError
+import com.circle.modularwallets.core.utils.rpc.ParseInterceptor
+import com.circle.modularwallets.core.utils.rpc.getAppInfo
+import com.circle.modularwallets.core.utils.rpc.getBodyString
+import com.circle.modularwallets.core.utils.rpc.getMoshi
+import okhttp3.Interceptor
+import okhttp3.OkHttpClient
+import okhttp3.logging.HttpLoggingInterceptor
+import retrofit2.Retrofit
+import retrofit2.converter.moshi.MoshiConverterFactory
+import java.io.IOException
+import java.net.SocketTimeoutException
+import java.util.concurrent.TimeUnit
+
+internal class RetrofitProvider {
+
+    fun get(context: Context, baseUrl: String, config: HttpRpcClientOptions): Retrofit {
+        val splitUrl = baseUrl.split("?")
+        val finalBaseUrl = if (TextUtils.isEmpty(splitUrl[0])) {
+            "https://modular-sdk.circle.com/v1/rpc/w3s/buidl/" // placeholder
+        } else if (splitUrl[0].endsWith("/")) {
+            splitUrl[0]
+        } else {
+            "${splitUrl[0]}/"
+        }
+
+        val appInfo = getAppInfo(context)
+        val clientBuilder = OkHttpClient.Builder()
+        val requestInterceptor = Interceptor { chain ->
+            val original = chain.request()
+            try {
+                chain.proceed(
+                    original.newBuilder()
+                        .apply {
+                            config.headers?.let {
+                                it.forEach { entry -> header(entry.key, entry.value) }
+                            }
+                        }
+                        .header("X-AppInfo", appInfo)
+                        .method(original.method, original.body)
+                        .build()
+                )
+            } catch (e: Throwable) {
+                val body = getBodyString(original.body)
+                val url = original.url.toString()
+                when (e) {
+                    is SocketTimeoutException -> throw IOException(
+                        TimeoutError(body, url)
+                    )
+
+                    is IOException -> throw e
+                    is BaseError -> throw IOException(
+                        e
+                    )
+
+                    else -> throw IOException(
+                        HttpRequestError(
+                            body = body,
+                            cause = e,
+                            url = url
+                        )
+                    )
+                }
+            }
+        }
+        clientBuilder.addInterceptor(requestInterceptor)
+        clientBuilder.addInterceptor(ParseInterceptor)
+        clientBuilder.readTimeout(120, TimeUnit.SECONDS)
+            .writeTimeout(120, TimeUnit.SECONDS)
+        val moshi = getMoshi()
+        if (BuildConfig.INTERNAL_BUILD) {
+            val logging =
+                HttpLoggingInterceptor { message: String? -> Log.d("<Circle> Http", message!!) }
+            logging.setLevel(HttpLoggingInterceptor.Level.BODY)
+            clientBuilder.addInterceptor(logging)
+        }
+        return Retrofit.Builder()
+            .baseUrl(finalBaseUrl)
+            .addConverterFactory(MoshiConverterFactory.create(moshi))
+            .client(clientBuilder.build())
+            .build()
+    }
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/Extensions.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/Extensions.kt
new file mode 100644
index 0000000..d806cbe
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/Extensions.kt
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.utils
+
+import kotlin.reflect.full.memberProperties
+
+inline fun <reified T : Any> T.toMap(): Map<String, Any?> {
+    val props = T::class.memberProperties.associateBy { it.name }
+    return props.keys.associateWith { props[it]?.get(this) }
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/JsonConversionUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/JsonConversionUtils.kt
new file mode 100644
index 0000000..ece1760
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/JsonConversionUtils.kt
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils
+
+import com.google.gson.Gson
+import com.squareup.moshi.JsonAdapter
+import com.squareup.moshi.Moshi
+import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
+
+
+internal fun toJson(obj: Any?): String {
+    obj ?: return ""
+    if (obj is String) {
+        return obj
+    }
+    return Gson().toJson(obj)
+}
+
+internal fun <T> fromJson(jsonString: String, type: Class<T>): T? {
+    val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
+    val adapter: JsonAdapter<T> = moshi.adapter(type)
+    return adapter.fromJson(jsonString)
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/Logger.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/Logger.kt
new file mode 100644
index 0000000..27f5407
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/Logger.kt
@@ -0,0 +1,90 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils
+
+import android.util.Log
+import com.circle.modularwallets.core.BuildConfig
+import org.json.JSONObject
+
+internal object Logger {
+    private const val TAG = "<Circle>"
+    private val isLogEnabled: Boolean
+        get() = BuildConfig.INTERNAL_BUILD
+
+    fun sdkTag(tag: String?): String {
+        return tag?.let { "$TAG $tag" } ?: TAG
+    }
+
+    fun i(tag: String? = null, msg: String, tr: Throwable? = null) {
+        if (!isLogEnabled) return
+        if (tr != null) {
+            Log.i(sdkTag(tag), msg, tr)
+        } else {
+            Log.i(sdkTag(tag), msg)
+        }
+    }
+
+    fun d(tag: String? = null, msg: String, tr: Throwable? = null) {
+        if (!isLogEnabled) return
+        if (tr != null) {
+            Log.d(sdkTag(tag), msg, tr)
+        } else {
+            Log.d(sdkTag(tag), msg)
+        }
+    }
+
+    fun w(tag: String? = null, msg: String, tr: Throwable? = null) {
+        if (!isLogEnabled) return
+        if (tr != null) {
+            Log.w(sdkTag(tag), msg, tr)
+        } else {
+            Log.w(sdkTag(tag), msg)
+        }
+    }
+
+    @JvmStatic
+    @JvmOverloads
+    fun e(tag: String? = null, msg: String, tr: Throwable? = null) {
+        if (!isLogEnabled) return
+        if (tr != null) {
+            Log.e(sdkTag(tag), msg, tr)
+        } else {
+            Log.e(sdkTag(tag), msg)
+        }
+    }
+}
+
+fun prettyPrint(args: Map<String, Any?>): String {
+    val entries = args.entries
+        .mapNotNull { (key, value) ->
+            if (value == null || value == false) null else key to value
+        }
+
+    val maxLength = entries.fold(0) { acc, (key) ->
+        maxOf(acc, key.length)
+    }
+
+    return entries.joinToString("\n") { (key, value) ->
+        "  ${"${key}:".padEnd(maxLength + 1)}  $value"
+    }
+}
+
+fun prettyPrintJson(obj: Any?): String {
+    return JSONObject(toJson(obj)).toString(2)
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/NonceManager.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/NonceManager.kt
new file mode 100644
index 0000000..3245aba
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/NonceManager.kt
@@ -0,0 +1,83 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils
+
+import java.math.BigInteger
+
+data class FunctionParameters(val address: String, val chainId: Long)
+
+interface NonceManagerSource {
+    fun get(parameters: FunctionParameters): BigInteger
+    fun set(parameters: FunctionParameters, nonce: BigInteger)
+}
+
+internal class NonceManager(private val source: NonceManagerSource) {
+    private val deltaMap = mutableMapOf<String, BigInteger>()
+    private val nonceMap = mutableMapOf<String, BigInteger>()
+
+    private fun getKey(params: FunctionParameters) = "${params.address}.${params.chainId}"
+    /**
+     * Increase delta
+     * Update nonceMap with value (source nonce or previousNonce + 1) + delta.
+     * The value will be used as previousNonce next time.
+     * */
+    fun consume(params: FunctionParameters): BigInteger {
+        val key = getKey(params)
+        increment(params)
+        val nonce = get(params)
+        source.set(params, nonce)
+        nonceMap[key] = nonce
+        return nonce
+    }
+    /** Increase delta */
+    private fun increment(params: FunctionParameters) {
+        val key = getKey(params)
+        val delta = deltaMap[key] ?: BigInteger.ZERO
+        deltaMap[key] = delta.plus(BigInteger.ONE)
+    }
+    /** Return (source nonce or previousNonce + 1) + delta */
+    fun get(params: FunctionParameters): BigInteger {
+        val key = getKey(params)
+        val delta = deltaMap[key] ?: BigInteger.ZERO
+        val nonce = internalGet(params, key)
+        return delta + nonce
+    }
+    /** Reset delta */
+    private fun reset(params: FunctionParameters) {
+        val key = getKey(params)
+        deltaMap.remove(key)
+    }
+    /** Return source nonce or previousNonce + 1  */
+    private fun internalGet(params: FunctionParameters, key: String): BigInteger {
+        val nonce: BigInteger
+        try {
+            val fetchedNonce = source.get(params)
+            val previousNonce = nonceMap[key] ?: BigInteger.ZERO
+            if (previousNonce > BigInteger.ZERO && fetchedNonce <= previousNonce) {
+                nonce = previousNonce.plus(BigInteger.ONE)
+            } else {
+                nonceMap.remove(key)
+                nonce = fetchedNonce
+            }
+        } finally {
+            reset(params)
+        }
+        return nonce
+    }
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeAbiParametersUtil.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeAbiParametersUtil.kt
new file mode 100644
index 0000000..996d9fb
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeAbiParametersUtil.kt
@@ -0,0 +1,28 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.abi
+
+import org.web3j.abi.DefaultFunctionEncoder
+import org.web3j.abi.datatypes.Type
+
+fun encodeAbiParameters(parameters: List<Type<*>>): String {
+    return "0x${
+        DefaultFunctionEncoder().encodeParameters(parameters)
+    }"
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeCallDataUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeCallDataUtils.kt
new file mode 100644
index 0000000..7f33a53
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeCallDataUtils.kt
@@ -0,0 +1,95 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.abi
+
+import com.circle.modularwallets.core.errors.InvalidAddressError
+import com.circle.modularwallets.core.models.EncodeCallDataArg
+import org.web3j.abi.FunctionEncoder
+import org.web3j.abi.datatypes.Address
+import org.web3j.abi.datatypes.DynamicArray
+import org.web3j.abi.datatypes.DynamicBytes
+import org.web3j.abi.datatypes.DynamicStruct
+import org.web3j.abi.datatypes.Function
+import org.web3j.abi.datatypes.Type
+import org.web3j.abi.datatypes.generated.Uint256
+import org.web3j.utils.Numeric
+import java.math.BigInteger
+
+/**
+ * Encodes the argument into calldata for executing a User Operation.
+ *
+ * @param arg The call data argument.
+ * @return The encoded call data.
+ */
+internal fun encodeCallData(arg: EncodeCallDataArg): String {
+    if (!isAddress(arg.to)) {
+        throw InvalidAddressError(arg.to)
+    }
+
+    val function =
+        Function(
+            "execute",
+            listOf<Type<*>>(
+                Address(arg.to),
+                Uint256(arg.value ?: BigInteger.ZERO),
+                DynamicBytes(Numeric.hexStringToByteArray(arg.data ?: "0x"))
+            ),
+            mutableListOf(),
+        )
+    return FunctionEncoder.encode(function)
+}
+
+private fun isAddress(to: String): Boolean {
+    val addressRegex = Regex("^0x[a-fA-F0-9]{40}$")
+    return addressRegex.matches(to)
+}
+
+/**
+ * Encodes the array of arguments into calldata for executing a User Operation.
+ *
+ * @param args The array of call data arguments.
+ * @return The encoded call data.
+ */
+internal fun encodeCallData(args: Array<EncodeCallDataArg>): String {
+    if (args.size == 1) {
+        return encodeCallData(args[0])
+    }
+    if (args.isEmpty()) { // empty call
+        return "0x34fcd5be00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000000"
+    }
+    val tupleArray: MutableList<DynamicStruct> = mutableListOf()
+    for (arg in args) {
+        tupleArray.add(
+            DynamicStruct(
+                Address(arg.to),
+                Uint256(arg.value ?: BigInteger.ZERO),
+                DynamicBytes(Numeric.hexStringToByteArray(arg.data ?: "0x"))
+            )
+        )
+    }
+    val function =
+        Function(
+            "executeBatch",
+            listOf<Type<*>>(
+                DynamicArray<DynamicStruct>(DynamicStruct::class.java, tupleArray),
+            ),
+            mutableListOf(),
+        )
+    return FunctionEncoder.encode(function)
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeContractExecutionUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeContractExecutionUtils.kt
new file mode 100644
index 0000000..336238f
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeContractExecutionUtils.kt
@@ -0,0 +1,125 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.abi
+
+import com.circle.modularwallets.core.models.EncodeCallDataArg
+import org.web3j.protocol.core.methods.response.AbiDefinition
+import java.math.BigInteger
+
+/**
+ * Encodes a contract execution into calldata for executing a User Operation.
+ *
+ * @param to The recipient address.
+ * @param abiSignature The ABI signature.
+ * @param args The arguments for the function call.
+ * @param value The value to send with the transaction.
+ * @return The encoded call data.
+ */
+
+@JvmOverloads
+fun encodeContractExecution(
+    to: String,
+    abiSignature: String,
+    args: Array<Any> = emptyArray(),
+    value: BigInteger
+): String {
+    val encodedAbi = encodeFromAbiSignature(abiSignature, args)
+    val arg = EncodeCallDataArg(to, value, encodedAbi)
+    return encodeCallData(arg)
+}
+
+internal fun encodeFromAbiSignature(
+    abiSignature: String,
+    args: Array<Any> = emptyArray(),
+): String {
+    val abiDefinition = getAbiDefinitionFromAbiSignature(abiSignature)
+    val encodedAbi = encodeFunctionData(abiDefinition.name, abiDefinition, args)
+    return encodedAbi
+}
+
+private fun getAbiDefinitionFromAbiSignature(abiSignature: String): AbiDefinition {
+    val functionName = getFunctionName(abiSignature)
+    val inputs: List<AbiDefinition.NamedType> = getNamedTypesFromAbiSignature(abiSignature)
+    val abiDefinition = AbiDefinition()
+    abiDefinition.name = functionName
+    abiDefinition.inputs = inputs
+    abiDefinition.type = "function"
+    abiDefinition.stateMutability = "nonpayable"
+
+    return abiDefinition
+}
+
+private fun getNamedTypesFromAbiSignature(abiSignature: String): List<AbiDefinition.NamedType> {
+    val regex = Regex("(\\w+)\\((.*)\\)")
+    val matchResult = regex.matchEntire(abiSignature)
+
+    val paramTypeString = matchResult?.groups?.get(2)?.value ?: ""
+    val paramTypes =
+        if (paramTypeString.isBlank()) emptyList() else parseParamTypes(paramTypeString)
+
+    return paramTypes.map { parseType(it) }
+}
+
+private fun parseParamTypes(paramTypeString: String): List<String> {
+    val paramTypes = mutableListOf<String>()
+    var depth = 0
+    val currentType = StringBuilder()
+
+    for (c in paramTypeString) {
+        if (c == ',' && depth == 0) {
+            paramTypes.add(currentType.toString())
+            currentType.setLength(0)
+        } else {
+            if (c == '(') {
+                depth++
+                currentType.append("tuple")
+            }
+            if (c == ')') depth--
+            currentType.append(c)
+        }
+    }
+    if (currentType.isNotEmpty()) {
+        paramTypes.add(currentType.toString())
+    }
+
+    return paramTypes
+}
+
+private fun parseType(type: String): AbiDefinition.NamedType {
+    return when {
+        type.startsWith("tuple") -> {
+            val componentsString = type.substringAfter("tuple(").substringBeforeLast(")")
+            val componentTypes = parseParamTypes(componentsString)
+            val components = componentTypes.map { parseType(it.trim()) }
+            AbiDefinition.NamedType("", "tuple", components, "", false)
+        }
+
+        else -> {
+            AbiDefinition.NamedType("", type)
+        }
+    }
+}
+
+private fun getFunctionName(abiSignature: String): String {
+    val regex = Regex("(\\w+)\\((.*)\\)")
+    val matchResult = regex.matchEntire(abiSignature)
+
+    val functionName = matchResult?.groups?.get(1)?.value ?: ""
+    return functionName
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeFunctionDataUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeFunctionDataUtils.kt
new file mode 100644
index 0000000..0a5eba5
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeFunctionDataUtils.kt
@@ -0,0 +1,763 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.abi
+
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.errors.BaseErrorParameters
+import com.google.gson.Gson
+import org.web3j.abi.FunctionEncoder
+import org.web3j.abi.TypeReference
+import org.web3j.abi.datatypes.AbiTypes
+import org.web3j.abi.datatypes.Address
+import org.web3j.abi.datatypes.Bool
+import org.web3j.abi.datatypes.DynamicArray
+import org.web3j.abi.datatypes.DynamicBytes
+import org.web3j.abi.datatypes.DynamicStruct
+import org.web3j.abi.datatypes.Function
+import org.web3j.abi.datatypes.StaticStruct
+import org.web3j.abi.datatypes.Type
+import org.web3j.abi.datatypes.Utf8String
+import org.web3j.abi.datatypes.generated.Bytes1
+import org.web3j.abi.datatypes.generated.Bytes10
+import org.web3j.abi.datatypes.generated.Bytes11
+import org.web3j.abi.datatypes.generated.Bytes12
+import org.web3j.abi.datatypes.generated.Bytes13
+import org.web3j.abi.datatypes.generated.Bytes14
+import org.web3j.abi.datatypes.generated.Bytes15
+import org.web3j.abi.datatypes.generated.Bytes16
+import org.web3j.abi.datatypes.generated.Bytes17
+import org.web3j.abi.datatypes.generated.Bytes18
+import org.web3j.abi.datatypes.generated.Bytes19
+import org.web3j.abi.datatypes.generated.Bytes2
+import org.web3j.abi.datatypes.generated.Bytes20
+import org.web3j.abi.datatypes.generated.Bytes21
+import org.web3j.abi.datatypes.generated.Bytes22
+import org.web3j.abi.datatypes.generated.Bytes23
+import org.web3j.abi.datatypes.generated.Bytes24
+import org.web3j.abi.datatypes.generated.Bytes25
+import org.web3j.abi.datatypes.generated.Bytes26
+import org.web3j.abi.datatypes.generated.Bytes27
+import org.web3j.abi.datatypes.generated.Bytes28
+import org.web3j.abi.datatypes.generated.Bytes29
+import org.web3j.abi.datatypes.generated.Bytes3
+import org.web3j.abi.datatypes.generated.Bytes30
+import org.web3j.abi.datatypes.generated.Bytes31
+import org.web3j.abi.datatypes.generated.Bytes32
+import org.web3j.abi.datatypes.generated.Bytes4
+import org.web3j.abi.datatypes.generated.Bytes5
+import org.web3j.abi.datatypes.generated.Bytes6
+import org.web3j.abi.datatypes.generated.Bytes7
+import org.web3j.abi.datatypes.generated.Bytes8
+import org.web3j.abi.datatypes.generated.Bytes9
+import org.web3j.abi.datatypes.generated.Int104
+import org.web3j.abi.datatypes.generated.Int112
+import org.web3j.abi.datatypes.generated.Int120
+import org.web3j.abi.datatypes.generated.Int128
+import org.web3j.abi.datatypes.generated.Int136
+import org.web3j.abi.datatypes.generated.Int144
+import org.web3j.abi.datatypes.generated.Int152
+import org.web3j.abi.datatypes.generated.Int16
+import org.web3j.abi.datatypes.generated.Int160
+import org.web3j.abi.datatypes.generated.Int168
+import org.web3j.abi.datatypes.generated.Int176
+import org.web3j.abi.datatypes.generated.Int184
+import org.web3j.abi.datatypes.generated.Int192
+import org.web3j.abi.datatypes.generated.Int200
+import org.web3j.abi.datatypes.generated.Int208
+import org.web3j.abi.datatypes.generated.Int216
+import org.web3j.abi.datatypes.generated.Int224
+import org.web3j.abi.datatypes.generated.Int232
+import org.web3j.abi.datatypes.generated.Int24
+import org.web3j.abi.datatypes.generated.Int240
+import org.web3j.abi.datatypes.generated.Int248
+import org.web3j.abi.datatypes.generated.Int256
+import org.web3j.abi.datatypes.generated.Int32
+import org.web3j.abi.datatypes.generated.Int40
+import org.web3j.abi.datatypes.generated.Int48
+import org.web3j.abi.datatypes.generated.Int56
+import org.web3j.abi.datatypes.generated.Int64
+import org.web3j.abi.datatypes.generated.Int72
+import org.web3j.abi.datatypes.generated.Int8
+import org.web3j.abi.datatypes.generated.Int80
+import org.web3j.abi.datatypes.generated.Int88
+import org.web3j.abi.datatypes.generated.Int96
+import org.web3j.abi.datatypes.generated.Uint104
+import org.web3j.abi.datatypes.generated.Uint112
+import org.web3j.abi.datatypes.generated.Uint120
+import org.web3j.abi.datatypes.generated.Uint128
+import org.web3j.abi.datatypes.generated.Uint136
+import org.web3j.abi.datatypes.generated.Uint144
+import org.web3j.abi.datatypes.generated.Uint152
+import org.web3j.abi.datatypes.generated.Uint16
+import org.web3j.abi.datatypes.generated.Uint160
+import org.web3j.abi.datatypes.generated.Uint168
+import org.web3j.abi.datatypes.generated.Uint176
+import org.web3j.abi.datatypes.generated.Uint184
+import org.web3j.abi.datatypes.generated.Uint192
+import org.web3j.abi.datatypes.generated.Uint200
+import org.web3j.abi.datatypes.generated.Uint208
+import org.web3j.abi.datatypes.generated.Uint216
+import org.web3j.abi.datatypes.generated.Uint224
+import org.web3j.abi.datatypes.generated.Uint232
+import org.web3j.abi.datatypes.generated.Uint24
+import org.web3j.abi.datatypes.generated.Uint240
+import org.web3j.abi.datatypes.generated.Uint248
+import org.web3j.abi.datatypes.generated.Uint256
+import org.web3j.abi.datatypes.generated.Uint32
+import org.web3j.abi.datatypes.generated.Uint40
+import org.web3j.abi.datatypes.generated.Uint48
+import org.web3j.abi.datatypes.generated.Uint56
+import org.web3j.abi.datatypes.generated.Uint64
+import org.web3j.abi.datatypes.generated.Uint72
+import org.web3j.abi.datatypes.generated.Uint8
+import org.web3j.abi.datatypes.generated.Uint80
+import org.web3j.abi.datatypes.generated.Uint88
+import org.web3j.abi.datatypes.generated.Uint96
+import org.web3j.crypto.Hash
+import org.web3j.protocol.core.methods.response.AbiDefinition
+import org.web3j.utils.Numeric
+import java.math.BigInteger
+
+const val TYPE_FUNCTION: String = "function"
+
+/**
+ * Encodes the function name and parameters into an ABI encoded value (4 byte selector & arguments).
+ *
+ * @param functionName The function to encode from the ABI.
+ * @param abiJson The ABI definition in JSON format.
+ * @param args The arguments for the function call.
+ * @return The encoded function call data.
+ */
+
+@Throws(Exception::class)
+@JvmOverloads
+fun encodeFunctionData(
+    functionName: String,
+    abiJson: String,
+    args: Array<Any> = emptyArray()
+): String {
+    val abiDefinition =
+        getAbiDefinition(functionName, abiJson) ?: throw BaseError("Invalid abiJson: $abiJson")
+    return encodeFunctionData(functionName, abiDefinition, args)
+}
+
+internal fun encodeFunctionData(
+    functionName: String,
+    abiDefinition: AbiDefinition,
+    args: Array<Any> = emptyArray()
+): String {
+    if (abiDefinition.inputs.size != args.size) {
+        throw BaseError("AbiEncodingLengthMismatchError")
+    }
+    try {
+        val finalInputs = inputFormat(abiDefinition.inputs, args)
+        val finalOutputs = emptyList<TypeReference<*>>()
+        val function =
+            Function(
+                functionName,
+                finalInputs,
+                finalOutputs
+            )
+        return encodeFunction(abiDefinition, function)
+    } catch (e: Throwable) {
+        if (e is BaseError) {
+            throw e
+        }
+        throw BaseError("encode function failed", BaseErrorParameters(e))
+    }
+}
+internal fun encodeFunction(abiDefinition: AbiDefinition, function: Function): String {
+    val oriAbi = FunctionEncoder.encode(function)
+    val encodedParameters = oriAbi.substring(10)
+    val methodSignature = buildMethodSignature(abiDefinition)
+    val methodId = buildMethodId(methodSignature)
+    return "${methodId}${encodedParameters}"
+}
+
+internal fun buildMethodSignature(abiDefinition: AbiDefinition): String {
+    val type = buildMethodSignatureType(abiDefinition.inputs)
+    return "${abiDefinition.name}$type"
+}
+
+internal fun buildMethodSignatureType(nameTypes: List<AbiDefinition.NamedType>): String {
+    val sb = StringBuilder()
+    sb.append("(")
+    nameTypes.forEachIndexed { index, input ->
+        if (input.type.startsWith("tuple")) {
+            val type = buildMethodSignatureType(input.components)
+            sb.append(input.type.replace("tuple", type))
+        } else {
+            sb.append(input.type)
+        }
+        if (index != nameTypes.size - 1) {
+            sb.append(",")
+        }
+    }
+    sb.append(")")
+    return sb.toString()
+}
+
+internal fun buildMethodId(methodSignature: String): String {
+    val input = methodSignature.toByteArray()
+    val hash = Hash.sha3(input)
+    return Numeric.toHexString(hash).substring(0, 10)
+}
+
+@Throws(Exception::class)
+private fun inputFormat(
+    inputNameTypes: List<AbiDefinition.NamedType>,
+    params: Array<Any>
+): List<Type<*>> {
+    val finalInputs: MutableList<Type<*>> = ArrayList()
+    for (i in inputNameTypes.indices) {
+        val type = inputNameTypes[i].type
+        val inputType: Type<*> = when {
+            type.endsWith("[]") -> {
+                val elementType = type.removeSuffix("[]")
+                val array = (params[i] as? Array<*>)?.map { it as Any }?.toTypedArray()
+                    ?: throw BaseError("Expected an array, but got ${params[i]::class}")
+
+                getDynamicArray(elementType, array)
+            }
+
+
+
+            type.startsWith("tuple") -> {
+                getTuple(params[i])
+            }
+
+            else -> {
+                getTypeInstance(type, params[i])
+            }
+        }
+        finalInputs.add(inputType)
+    }
+    return finalInputs
+}
+
+internal fun getTuple(param: Any): Type<*> {
+    return when (param) {
+        is StaticStruct -> param
+        is DynamicStruct -> param
+        is List<*> -> {
+            val tupleElements = param.filterIsInstance<Type<*>>()
+            val hasDynamicType = param.any { it is DynamicBytes || it is Utf8String || it is DynamicArray<*> }
+            if (hasDynamicType) {
+                DynamicStruct(tupleElements)
+            } else {
+                StaticStruct(tupleElements)
+            }
+        }
+
+        else -> {
+            val tupleElements = (param as? Array<*>)?.mapNotNull { it as? Type<*> }
+                ?: throw BaseError("Expected an array, but got ${param::class}")
+            val hasDynamicType = tupleElements.any { it is DynamicBytes || it is Utf8String || it is DynamicArray<*> }
+            if (hasDynamicType) {
+                DynamicStruct(tupleElements)
+            } else {
+                StaticStruct(tupleElements)
+            }
+        }
+    }
+}
+
+private fun getDynamicArray(type: String, param: Array<Any>): DynamicArray<*> {
+    return when (type) {
+        "address" -> DynamicArray(Address::class.java, param.map { Address(it.toString()) })
+        "bool" -> DynamicArray(Bool::class.java, param.map { Bool(it.toString().toBoolean()) })
+        "string" -> DynamicArray(Utf8String::class.java, param.map { Utf8String(it.toString()) })
+        "bytes" -> DynamicArray(
+            DynamicBytes::class.java,
+            param.map { DynamicBytes(Numeric.hexStringToByteArray(it.toString())) })
+
+        "uint8" -> DynamicArray(Uint8::class.java, param.map { Uint8(BigInteger(it.toString())) })
+        "int8" -> DynamicArray(Int8::class.java, param.map { Int8(BigInteger(it.toString())) })
+        "uint16" -> DynamicArray(
+            Uint16::class.java,
+            param.map { Uint16(BigInteger(it.toString())) })
+
+        "int16" -> DynamicArray(Int16::class.java, param.map { Int16(BigInteger(it.toString())) })
+        "uint24" -> DynamicArray(
+            Uint24::class.java,
+            param.map { Uint24(BigInteger(it.toString())) })
+
+        "int24" -> DynamicArray(Int24::class.java, param.map { Int24(BigInteger(it.toString())) })
+        "uint32" -> DynamicArray(
+            Uint32::class.java,
+            param.map { Uint32(BigInteger(it.toString())) })
+
+        "int32" -> DynamicArray(Int32::class.java, param.map { Int32(BigInteger(it.toString())) })
+        "uint40" -> DynamicArray(
+            Uint40::class.java,
+            param.map { Uint40(BigInteger(it.toString())) })
+
+        "int40" -> DynamicArray(Int40::class.java, param.map { Int40(BigInteger(it.toString())) })
+        "uint48" -> DynamicArray(
+            Uint48::class.java,
+            param.map { Uint48(BigInteger(it.toString())) })
+
+        "int48" -> DynamicArray(Int48::class.java, param.map { Int48(BigInteger(it.toString())) })
+        "uint56" -> DynamicArray(
+            Uint56::class.java,
+            param.map { Uint56(BigInteger(it.toString())) })
+
+        "int56" -> DynamicArray(Int56::class.java, param.map { Int56(BigInteger(it.toString())) })
+        "uint64" -> DynamicArray(
+            Uint64::class.java,
+            param.map { Uint64(BigInteger(it.toString())) })
+
+        "int64" -> DynamicArray(Int64::class.java, param.map { Int64(BigInteger(it.toString())) })
+        "uint72" -> DynamicArray(
+            Uint72::class.java,
+            param.map { Uint72(BigInteger(it.toString())) })
+
+        "int72" -> DynamicArray(Int72::class.java, param.map { Int72(BigInteger(it.toString())) })
+        "uint80" -> DynamicArray(
+            Uint80::class.java,
+            param.map { Uint80(BigInteger(it.toString())) })
+
+        "int80" -> DynamicArray(Int80::class.java, param.map { Int80(BigInteger(it.toString())) })
+        "uint88" -> DynamicArray(
+            Uint88::class.java,
+            param.map { Uint88(BigInteger(it.toString())) })
+
+        "int88" -> DynamicArray(Int88::class.java, param.map { Int88(BigInteger(it.toString())) })
+        "uint96" -> DynamicArray(
+            Uint96::class.java,
+            param.map { Uint96(BigInteger(it.toString())) })
+
+        "int96" -> DynamicArray(Int96::class.java, param.map { Int96(BigInteger(it.toString())) })
+        "uint104" -> DynamicArray(
+            Uint104::class.java,
+            param.map { Uint104(BigInteger(it.toString())) })
+
+        "int104" -> DynamicArray(
+            Int104::class.java,
+            param.map { Int104(BigInteger(it.toString())) })
+
+        "uint112" -> DynamicArray(
+            Uint112::class.java,
+            param.map { Uint112(BigInteger(it.toString())) })
+
+        "int112" -> DynamicArray(
+            Int112::class.java,
+            param.map { Int112(BigInteger(it.toString())) })
+
+        "uint120" -> DynamicArray(
+            Uint120::class.java,
+            param.map { Uint120(BigInteger(it.toString())) })
+
+        "int120" -> DynamicArray(
+            Int120::class.java,
+            param.map { Int120(BigInteger(it.toString())) })
+
+        "uint128" -> DynamicArray(
+            Uint128::class.java,
+            param.map { Uint128(BigInteger(it.toString())) })
+
+        "int128" -> DynamicArray(
+            Int128::class.java,
+            param.map { Int128(BigInteger(it.toString())) })
+
+        "uint136" -> DynamicArray(
+            Uint136::class.java,
+            param.map { Uint136(BigInteger(it.toString())) })
+
+        "int136" -> DynamicArray(
+            Int136::class.java,
+            param.map { Int136(BigInteger(it.toString())) })
+
+        "uint144" -> DynamicArray(
+            Uint144::class.java,
+            param.map { Uint144(BigInteger(it.toString())) })
+
+        "int144" -> DynamicArray(
+            Int144::class.java,
+            param.map { Int144(BigInteger(it.toString())) })
+
+        "uint152" -> DynamicArray(
+            Uint152::class.java,
+            param.map { Uint152(BigInteger(it.toString())) })
+
+        "int152" -> DynamicArray(
+            Int152::class.java,
+            param.map { Int152(BigInteger(it.toString())) })
+
+        "uint160" -> DynamicArray(
+            Uint160::class.java,
+            param.map { Uint160(BigInteger(it.toString())) })
+
+        "int160" -> DynamicArray(
+            Int160::class.java,
+            param.map { Int160(BigInteger(it.toString())) })
+
+        "uint168" -> DynamicArray(
+            Uint168::class.java,
+            param.map { Uint168(BigInteger(it.toString())) })
+
+        "int168" -> DynamicArray(
+            Int168::class.java,
+            param.map { Int168(BigInteger(it.toString())) })
+
+        "uint176" -> DynamicArray(
+            Uint176::class.java,
+            param.map { Uint176(BigInteger(it.toString())) })
+
+        "int176" -> DynamicArray(
+            Int176::class.java,
+            param.map { Int176(BigInteger(it.toString())) })
+
+        "uint184" -> DynamicArray(
+            Uint184::class.java,
+            param.map { Uint184(BigInteger(it.toString())) })
+
+        "int184" -> DynamicArray(
+            Int184::class.java,
+            param.map { Int184(BigInteger(it.toString())) })
+
+        "uint192" -> DynamicArray(
+            Uint192::class.java,
+            param.map { Uint192(BigInteger(it.toString())) })
+
+        "int192" -> DynamicArray(
+            Int192::class.java,
+            param.map { Int192(BigInteger(it.toString())) })
+
+        "uint200" -> DynamicArray(
+            Uint200::class.java,
+            param.map { Uint200(BigInteger(it.toString())) })
+
+        "int200" -> DynamicArray(
+            Int200::class.java,
+            param.map { Int200(BigInteger(it.toString())) })
+
+        "uint208" -> DynamicArray(
+            Uint208::class.java,
+            param.map { Uint208(BigInteger(it.toString())) })
+
+        "int208" -> DynamicArray(
+            Int208::class.java,
+            param.map { Int208(BigInteger(it.toString())) })
+
+        "uint216" -> DynamicArray(
+            Uint216::class.java,
+            param.map { Uint216(BigInteger(it.toString())) })
+
+        "int216" -> DynamicArray(
+            Int216::class.java,
+            param.map { Int216(BigInteger(it.toString())) })
+
+        "uint224" -> DynamicArray(
+            Uint224::class.java,
+            param.map { Uint224(BigInteger(it.toString())) })
+
+        "int224" -> DynamicArray(
+            Int224::class.java,
+            param.map { Int224(BigInteger(it.toString())) })
+
+        "uint232" -> DynamicArray(
+            Uint232::class.java,
+            param.map { Uint232(BigInteger(it.toString())) })
+
+        "int232" -> DynamicArray(
+            Int232::class.java,
+            param.map { Int232(BigInteger(it.toString())) })
+
+        "uint240" -> DynamicArray(
+            Uint240::class.java,
+            param.map { Uint240(BigInteger(it.toString())) })
+
+        "int240" -> DynamicArray(
+            Int240::class.java,
+            param.map { Int240(BigInteger(it.toString())) })
+
+        "uint248" -> DynamicArray(
+            Uint248::class.java,
+            param.map { Uint248(BigInteger(it.toString())) })
+
+        "int248" -> DynamicArray(
+            Int248::class.java,
+            param.map { Int248(BigInteger(it.toString())) })
+
+        "uint256" -> DynamicArray(
+            Uint256::class.java,
+            param.map { Uint256(BigInteger(it.toString())) })
+
+        "int256" -> DynamicArray(
+            Int256::class.java,
+            param.map { Int256(BigInteger(it.toString())) })
+
+        "bytes1" -> DynamicArray(
+            Bytes1::class.java,
+            param.map { Bytes1(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes2" -> DynamicArray(
+            Bytes2::class.java,
+            param.map { Bytes2(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes3" -> DynamicArray(
+            Bytes3::class.java,
+            param.map { Bytes3(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes4" -> DynamicArray(
+            Bytes4::class.java,
+            param.map { Bytes4(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes5" -> DynamicArray(
+            Bytes5::class.java,
+            param.map { Bytes5(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes6" -> DynamicArray(
+            Bytes6::class.java,
+            param.map { Bytes6(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes7" -> DynamicArray(
+            Bytes7::class.java,
+            param.map { Bytes7(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes8" -> DynamicArray(
+            Bytes8::class.java,
+            param.map { Bytes8(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes9" -> DynamicArray(
+            Bytes9::class.java,
+            param.map { Bytes9(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes10" -> DynamicArray(
+            Bytes10::class.java,
+            param.map { Bytes10(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes11" -> DynamicArray(
+            Bytes11::class.java,
+            param.map { Bytes11(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes12" -> DynamicArray(
+            Bytes12::class.java,
+            param.map { Bytes12(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes13" -> DynamicArray(
+            Bytes13::class.java,
+            param.map { Bytes13(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes14" -> DynamicArray(
+            Bytes14::class.java,
+            param.map { Bytes14(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes15" -> DynamicArray(
+            Bytes15::class.java,
+            param.map { Bytes15(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes16" -> DynamicArray(
+            Bytes16::class.java,
+            param.map { Bytes16(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes17" -> DynamicArray(
+            Bytes17::class.java,
+            param.map { Bytes17(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes18" -> DynamicArray(
+            Bytes18::class.java,
+            param.map { Bytes18(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes19" -> DynamicArray(
+            Bytes19::class.java,
+            param.map { Bytes19(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes20" -> DynamicArray(
+            Bytes20::class.java,
+            param.map { Bytes20(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes21" -> DynamicArray(
+            Bytes21::class.java,
+            param.map { Bytes21(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes22" -> DynamicArray(
+            Bytes22::class.java,
+            param.map { Bytes22(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes23" -> DynamicArray(
+            Bytes23::class.java,
+            param.map { Bytes23(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes24" -> DynamicArray(
+            Bytes24::class.java,
+            param.map { Bytes24(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes25" -> DynamicArray(
+            Bytes25::class.java,
+            param.map { Bytes25(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes26" -> DynamicArray(
+            Bytes26::class.java,
+            param.map { Bytes26(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes27" -> DynamicArray(
+            Bytes27::class.java,
+            param.map { Bytes27(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes28" -> DynamicArray(
+            Bytes28::class.java,
+            param.map { Bytes28(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes29" -> DynamicArray(
+            Bytes29::class.java,
+            param.map { Bytes29(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes30" -> DynamicArray(
+            Bytes30::class.java,
+            param.map { Bytes30(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes31" -> DynamicArray(
+            Bytes31::class.java,
+            param.map { Bytes31(Numeric.hexStringToByteArray(it.toString())) })
+
+        "bytes32" -> DynamicArray(
+            Bytes32::class.java,
+            param.map { Bytes32(Numeric.hexStringToByteArray(it.toString())) })
+
+        "tuple" -> DynamicArray(
+            Type::class.java,
+            param.map {
+                getTuple(it)
+            })
+
+        else -> throw BaseError("Unsupported type: $type")
+    }
+}
+
+private fun getTypeInstance(type: String, value: Any): Type<*> {
+    return when (type) {
+        "address" -> Address(value.toString())
+        "bool" -> Bool(value.toString().toBoolean())
+        "string" -> Utf8String(value.toString())
+        "bytes" -> DynamicBytes(Numeric.hexStringToByteArray(value.toString()))
+        "uint8" -> Uint8(BigInteger(value.toString()))
+        "int8" -> Int8(BigInteger(value.toString()))
+        "uint16" -> Uint16(BigInteger(value.toString()))
+        "int16" -> Int16(BigInteger(value.toString()))
+        "uint24" -> Uint24(BigInteger(value.toString()))
+        "int24" -> Int24(BigInteger(value.toString()))
+        "uint32" -> Uint32(BigInteger(value.toString()))
+        "int32" -> Int32(BigInteger(value.toString()))
+        "uint40" -> Uint40(BigInteger(value.toString()))
+        "int40" -> Int40(BigInteger(value.toString()))
+        "uint48" -> Uint48(BigInteger(value.toString()))
+        "int48" -> Int48(BigInteger(value.toString()))
+        "uint56" -> Uint56(BigInteger(value.toString()))
+        "int56" -> Int56(BigInteger(value.toString()))
+        "uint64" -> Uint64(BigInteger(value.toString()))
+        "int64" -> Int64(BigInteger(value.toString()))
+        "uint72" -> Uint72(BigInteger(value.toString()))
+        "int72" -> Int72(BigInteger(value.toString()))
+        "uint80" -> Uint80(BigInteger(value.toString()))
+        "int80" -> Int80(BigInteger(value.toString()))
+        "uint88" -> Uint88(BigInteger(value.toString()))
+        "int88" -> Int88(BigInteger(value.toString()))
+        "uint96" -> Uint96(BigInteger(value.toString()))
+        "int96" -> Int96(BigInteger(value.toString()))
+        "uint104" -> Uint104(BigInteger(value.toString()))
+        "int104" -> Int104(BigInteger(value.toString()))
+        "uint112" -> Uint112(BigInteger(value.toString()))
+        "int112" -> Int112(BigInteger(value.toString()))
+        "uint120" -> Uint120(BigInteger(value.toString()))
+        "int120" -> Int120(BigInteger(value.toString()))
+        "uint128" -> Uint128(BigInteger(value.toString()))
+        "int128" -> Int128(BigInteger(value.toString()))
+        "uint136" -> Uint136(BigInteger(value.toString()))
+        "int136" -> Int136(BigInteger(value.toString()))
+        "uint144" -> Uint144(BigInteger(value.toString()))
+        "int144" -> Int144(BigInteger(value.toString()))
+        "uint152" -> Uint152(BigInteger(value.toString()))
+        "int152" -> Int152(BigInteger(value.toString()))
+        "uint160" -> Uint160(BigInteger(value.toString()))
+        "int160" -> Int160(BigInteger(value.toString()))
+        "uint168" -> Uint168(BigInteger(value.toString()))
+        "int168" -> Int168(BigInteger(value.toString()))
+        "uint176" -> Uint176(BigInteger(value.toString()))
+        "int176" -> Int176(BigInteger(value.toString()))
+        "uint184" -> Uint184(BigInteger(value.toString()))
+        "int184" -> Int184(BigInteger(value.toString()))
+        "uint192" -> Uint192(BigInteger(value.toString()))
+        "int192" -> Int192(BigInteger(value.toString()))
+        "uint200" -> Uint200(BigInteger(value.toString()))
+        "int200" -> Int200(BigInteger(value.toString()))
+        "uint208" -> Uint208(BigInteger(value.toString()))
+        "int208" -> Int208(BigInteger(value.toString()))
+        "uint216" -> Uint216(BigInteger(value.toString()))
+        "int216" -> Int216(BigInteger(value.toString()))
+        "uint224" -> Uint224(BigInteger(value.toString()))
+        "int224" -> Int224(BigInteger(value.toString()))
+        "uint232" -> Uint232(BigInteger(value.toString()))
+        "int232" -> Int232(BigInteger(value.toString()))
+        "uint240" -> Uint240(BigInteger(value.toString()))
+        "int240" -> Int240(BigInteger(value.toString()))
+        "uint248" -> Uint248(BigInteger(value.toString()))
+        "int248" -> Int248(BigInteger(value.toString()))
+        "uint256" -> Uint256(BigInteger(value.toString()))
+        "int256" -> Int256(BigInteger(value.toString()))
+        "bytes1" -> Bytes1(Numeric.hexStringToByteArray(value.toString()))
+        "bytes2" -> Bytes2(Numeric.hexStringToByteArray(value.toString()))
+        "bytes3" -> Bytes3(Numeric.hexStringToByteArray(value.toString()))
+        "bytes4" -> Bytes4(Numeric.hexStringToByteArray(value.toString()))
+        "bytes5" -> Bytes5(Numeric.hexStringToByteArray(value.toString()))
+        "bytes6" -> Bytes6(Numeric.hexStringToByteArray(value.toString()))
+        "bytes7" -> Bytes7(Numeric.hexStringToByteArray(value.toString()))
+        "bytes8" -> Bytes8(Numeric.hexStringToByteArray(value.toString()))
+        "bytes9" -> Bytes9(Numeric.hexStringToByteArray(value.toString()))
+        "bytes10" -> Bytes10(Numeric.hexStringToByteArray(value.toString()))
+        "bytes11" -> Bytes11(Numeric.hexStringToByteArray(value.toString()))
+        "bytes12" -> Bytes12(Numeric.hexStringToByteArray(value.toString()))
+        "bytes13" -> Bytes13(Numeric.hexStringToByteArray(value.toString()))
+        "bytes14" -> Bytes14(Numeric.hexStringToByteArray(value.toString()))
+        "bytes15" -> Bytes15(Numeric.hexStringToByteArray(value.toString()))
+        "bytes16" -> Bytes16(Numeric.hexStringToByteArray(value.toString()))
+        "bytes17" -> Bytes17(Numeric.hexStringToByteArray(value.toString()))
+        "bytes18" -> Bytes18(Numeric.hexStringToByteArray(value.toString()))
+        "bytes19" -> Bytes19(Numeric.hexStringToByteArray(value.toString()))
+        "bytes20" -> Bytes20(Numeric.hexStringToByteArray(value.toString()))
+        "bytes21" -> Bytes21(Numeric.hexStringToByteArray(value.toString()))
+        "bytes22" -> Bytes22(Numeric.hexStringToByteArray(value.toString()))
+        "bytes23" -> Bytes23(Numeric.hexStringToByteArray(value.toString()))
+        "bytes24" -> Bytes24(Numeric.hexStringToByteArray(value.toString()))
+        "bytes25" -> Bytes25(Numeric.hexStringToByteArray(value.toString()))
+        "bytes26" -> Bytes26(Numeric.hexStringToByteArray(value.toString()))
+        "bytes27" -> Bytes27(Numeric.hexStringToByteArray(value.toString()))
+        "bytes28" -> Bytes28(Numeric.hexStringToByteArray(value.toString()))
+        "bytes29" -> Bytes29(Numeric.hexStringToByteArray(value.toString()))
+        "bytes30" -> Bytes30(Numeric.hexStringToByteArray(value.toString()))
+        "bytes31" -> Bytes31(Numeric.hexStringToByteArray(value.toString()))
+        "bytes32" -> Bytes32(Numeric.hexStringToByteArray(value.toString()))
+        else -> throw BaseError("Unsupported type: $type")
+    }
+}
+
+private fun getAbiDefinition(name: String, contractAbi: String?): AbiDefinition? {
+    val abiDefinitions = Gson().fromJson(contractAbi, Array<AbiDefinition>::class.java)
+        ?: return null
+    var result: AbiDefinition? = null
+    for (abiDefinition in abiDefinitions) {
+        if (TYPE_FUNCTION == abiDefinition.type && name == abiDefinition.name) {
+            result = abiDefinition
+            break
+        }
+    }
+    return result
+}
+
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodePackedUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodePackedUtils.kt
new file mode 100644
index 0000000..0860fd6
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodePackedUtils.kt
@@ -0,0 +1,145 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.abi
+
+import org.web3j.abi.TypeEncoder
+import org.web3j.abi.datatypes.Address
+import org.web3j.abi.datatypes.Array
+import org.web3j.abi.datatypes.Bool
+import org.web3j.abi.datatypes.Bytes
+import org.web3j.abi.datatypes.BytesType
+import org.web3j.abi.datatypes.DynamicArray
+import org.web3j.abi.datatypes.DynamicBytes
+import org.web3j.abi.datatypes.DynamicStruct
+import org.web3j.abi.datatypes.Fixed
+import org.web3j.abi.datatypes.FixedPointType
+import org.web3j.abi.datatypes.NumericType
+import org.web3j.abi.datatypes.StaticArray
+import org.web3j.abi.datatypes.StaticStruct
+import org.web3j.abi.datatypes.Type
+import org.web3j.abi.datatypes.Ufixed
+import org.web3j.abi.datatypes.Utf8String
+import org.web3j.abi.datatypes.primitive.PrimitiveType
+import org.web3j.utils.Numeric
+import java.nio.charset.StandardCharsets
+
+@Throws(Exception::class)
+fun encodePacked(parameters: List<Type<*>>): String {
+    val result = StringBuilder()
+    for (parameter in parameters) {
+        result.append(encodePacked(parameter))
+    }
+    return "0x$result"
+}
+
+private fun encodePacked(parameter: Type<*>): String {
+    return when (parameter) {
+        is Utf8String -> {
+            Numeric.toHexStringNoPrefix(
+                parameter.value.toByteArray(StandardCharsets.UTF_8)
+            )
+        }
+
+        is DynamicBytes -> {
+            Numeric.toHexStringNoPrefix(parameter.value)
+        }
+
+        is DynamicArray<*> -> {
+            arrayEncodePacked(parameter)
+        }
+
+        is StaticArray<*> -> {
+            arrayEncodePacked(parameter)
+        }
+
+        is PrimitiveType<*> -> {
+            encodePacked(parameter.toSolidityType())
+        }
+
+        else -> {
+            removePadding(TypeEncoder.encode(parameter), parameter)
+        }
+    }
+}
+
+private fun removePadding(encodedValue: String, parameter: Type<*>): String {
+    when (parameter) {
+        is NumericType -> {
+            if (parameter is Ufixed || parameter is Fixed) {
+                return encodedValue
+            }
+            return encodedValue.substring(64 - parameter.bitSize / 4, 64)
+        }
+
+        is Address -> {
+            return encodedValue.substring(64 - parameter.toUint().bitSize / 4, 64)
+        }
+
+        is Bool -> {
+            return encodedValue.substring(62, 64)
+        }
+
+        is Bytes -> {
+            return encodedValue.substring(0, (parameter as BytesType).value.size * 2)
+        }
+
+        is Utf8String -> {
+            val length =
+                parameter.value.toByteArray(StandardCharsets.UTF_8).size
+            return encodedValue.substring(64, 64 + length * 2)
+        }
+
+        is DynamicBytes -> {
+            return encodedValue.substring(
+                64, 64 + parameter.value.size * 2
+            )
+        }
+
+        else -> {
+            throw UnsupportedOperationException(
+                "Type cannot be encoded: " + parameter.javaClass
+            )
+        }
+    }
+}
+
+private fun <T : Type<*>> isSupportingEncodedPacked(value: Array<T>): Boolean {
+    return !(Utf8String::class.java.isAssignableFrom(value.componentType)
+            || DynamicStruct::class.java.isAssignableFrom(value.componentType)
+            || DynamicArray::class.java.isAssignableFrom(value.componentType)
+            || StaticStruct::class.java.isAssignableFrom(value.componentType)
+            || FixedPointType::class.java.isAssignableFrom(value.componentType)
+            || DynamicBytes::class.java.isAssignableFrom(value.componentType))
+}
+
+private fun <T : Type<*>> arrayEncodePacked(values: Array<T>): String {
+    if (isSupportingEncodedPacked(values)) {
+        if (values.value.isEmpty()) {
+            return ""
+        }
+        if (values is DynamicArray<*>) {
+            return TypeEncoder.encode(values).substring(64)
+        } else if (values is StaticArray<*>) {
+            return TypeEncoder.encode(values)
+        }
+    }
+    throw UnsupportedOperationException(
+        "Type cannot be packed encoded: " + values.javaClass
+    )
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeTransferUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeTransferUtils.kt
new file mode 100644
index 0000000..826256a
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/abi/EncodeTransferUtils.kt
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.abi
+
+import com.circle.modularwallets.core.constants.ABI_ERC20
+import com.circle.modularwallets.core.constants.ABI_FUNCTION_TRANSFER
+import com.circle.modularwallets.core.constants.CONTRACT_ADDRESS
+import com.circle.modularwallets.core.models.EncodeCallDataArg
+import com.circle.modularwallets.core.models.EncodeTransferResult
+import com.circle.modularwallets.core.models.Token
+import java.math.BigInteger
+
+/**
+ * Encodes an ERC20 token transfer into calldata for executing a User Operation.
+ *
+ * @param to The recipient address.
+ * @param token The token contract address or the name of [Token] enum .
+ * @param amount The amount to transfer.
+ * @return The encoded transfer abi and contract address.
+ */
+@Throws(Exception::class)
+fun encodeTransfer(
+    to: String,
+    token: String,
+    amount: BigInteger
+): EncodeTransferResult {
+    val abiParameters: Array<Any> = arrayOf(to, amount)
+    val encodedAbi = encodeFunctionData(ABI_FUNCTION_TRANSFER, ABI_ERC20, abiParameters)
+    return EncodeTransferResult(data = encodedAbi, to = CONTRACT_ADDRESS[token] ?: token)
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/data/ConcatUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/data/ConcatUtils.kt
new file mode 100644
index 0000000..6ea0a51
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/data/ConcatUtils.kt
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.data
+
+/**
+ * Concatenates multiple strings, removing any "0x" prefixes, and returns the result with a "0x" prefix.
+ *
+ * @param values The strings to concatenate.
+ * @return The concatenated string with a "0x" prefix.
+ */
+fun concat(vararg values: String): String {
+    val concatenated = values.joinToString("") { it.replace("0x", "") }
+    return "0x$concatenated"
+}
+
+/**
+ * Concatenates multiple byte arrays into a single byte array.
+ *
+ * @param values The byte arrays to concatenate.
+ * @return The concatenated byte array.
+ */
+fun concat(vararg values: ByteArray): ByteArray {
+    val totalLength = values.sumOf { it.size }
+
+    val result = ByteArray(totalLength)
+
+    var offset = 0
+    for (arr in values) {
+        System.arraycopy(arr, 0, result, offset, arr.size)
+        offset += arr.size
+    }
+    return result
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/data/IsHexUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/data/IsHexUtils.kt
new file mode 100644
index 0000000..d253c3f
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/data/IsHexUtils.kt
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.data
+
+/**
+ * Checks if the given value is a hexadecimal string.
+ *
+ * @param value The value to check.
+ * @param strict If true, the value must strictly match the hexadecimal pattern (starting with "0x" and followed by hexadecimal characters). If false, the value only needs to start with "0x".
+ * @return True if the value is a hexadecimal string, false otherwise.
+ */
+
+@JvmOverloads
+fun isHex(value: Any?, strict: Boolean = true): Boolean {
+    if (value == null) return false
+    if (value !is String) return false
+    return if (strict) "^0x[0-9a-fA-F]*$".toRegex().matches(value) else value.startsWith("0x")
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/data/PadUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/data/PadUtils.kt
new file mode 100644
index 0000000..8860ddd
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/data/PadUtils.kt
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.data
+
+import com.circle.modularwallets.core.errors.BaseError
+
+/**
+ * Pads the given byte array to the specified size.
+ *
+ * @param bytes The byte array to pad.
+ * @param size The size to pad the byte array to. Default is 32.
+ * @param isRight If true, padding is added to the right. If false, padding is added to the left. Default is false.
+ * @return The padded byte array.
+ * @throws BaseError if the size of the byte array exceeds the specified size.
+ */
+@JvmOverloads
+@Throws(Exception::class)
+fun pad(bytes: ByteArray, size: Int = 32, isRight: Boolean = false): ByteArray {
+    if (bytes.size > size) {
+        throw BaseError("SizeExceedsPaddingSizeError")
+    }
+    val paddedBytes = ByteArray(size)
+
+    for (i in 0 until size) {
+        val padEnd = isRight
+        paddedBytes[if (padEnd) i else size - i - 1] =
+            if (padEnd)
+                bytes.getOrElse(i) { 0 }
+            else
+                bytes.getOrElse(bytes.size - i - 1) { 0 }
+    }
+    return paddedBytes
+}
+
+/**
+ * Pads the given hexadecimal string to the specified size.
+ *
+ * @param hex The hexadecimal string to pad.
+ * @param size The size to pad the hexadecimal string to. Default is 32.
+ * @param isRight If true, padding is added to the right. If false, padding is added to the left. Default is false.
+ * @return The padded hexadecimal string with a "0x" prefix.
+ * @throws BaseError if the length of the hexadecimal string exceeds the specified size.
+ */
+@JvmOverloads
+@Throws(Exception::class)
+fun pad(hex: String?, size: Int = 32, isRight: Boolean = false): String {
+    hex ?: return ""
+    val hexCleaned = hex.removePrefix("0x").removePrefix("0X")
+    val length = size * 2
+    if (hexCleaned.length > length) {
+        throw BaseError("SizeExceedsPaddingSizeError")
+    }
+    val result = "0x" + if (isRight) {
+        hexCleaned.padEnd(length, '0')
+    } else {
+        hexCleaned.padStart(length, '0')
+    }
+    return result
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/data/SliceUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/data/SliceUtils.kt
new file mode 100644
index 0000000..0a0f467
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/data/SliceUtils.kt
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.data
+
+/**
+ * Slices the given hexadecimal string from the specified start index to the end index.
+ *
+ * @param value The hexadecimal string to slice.
+ * @param start The start index for slicing (in bytes). Default is 0.
+ * @param end The end index for slicing (in bytes). Default is the length of the string divided by 2.
+ * @param strict If true, the sliced value must strictly match the hexadecimal pattern (starting with "0x" and followed by hexadecimal characters). Default is false.
+ * @return The sliced hexadecimal string with a "0x" prefix.
+ * @throws IllegalArgumentException if the sliced value does not match the hexadecimal pattern when strict is true.
+ */
+@JvmOverloads
+fun slice(
+    value: String,
+    start: Int? = null,
+    end: Int? = null,
+    strict: Boolean = false
+): String {
+    val cleanValue = value.removePrefix("0x")
+    val startIndex = (start ?: 0) * 2
+    val endIndex = (end ?: (cleanValue.length / 2)) * 2
+    val slicedValue = "0x${cleanValue.slice(startIndex until endIndex)}"
+    if (strict) {
+        require(slicedValue.matches(Regex("0x[0-9a-fA-F]*"))) {
+            "Invalid hexadecimal string"
+        }
+    }
+
+    return slicedValue
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/encoding/HexConversionUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/encoding/HexConversionUtils.kt
new file mode 100644
index 0000000..00fe6c1
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/encoding/HexConversionUtils.kt
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.encoding
+
+import com.circle.modularwallets.core.errors.IntegerOutOfRangeError
+import java.math.BigInteger
+
+/**
+ * Converts a BigInteger to a hexadecimal string with a "0x" prefix.
+ *
+ * @param num The BigInteger to convert.
+ * @return The hexadecimal string representation of the BigInteger with a "0x" prefix, or null if the input is null.
+ */
+fun bigIntegerToHex(num: BigInteger?): String? {
+    num ?: return null
+    // Check num MUST NOT be negative
+    if (num.signum() < 0) {
+        throw IntegerOutOfRangeError()
+    }
+    return "0x${num.toString(16)}"
+}
+
+/**
+ * Converts a hexadecimal string to a BigInteger.
+ *
+ * @param hex The hexadecimal string to convert.
+ * @return The BigInteger representation of the hexadecimal string, or null if the input is null.
+ */
+fun hexToBigInteger(hex: String?): BigInteger? {
+    hex ?: return null
+    return BigInteger(hex.removePrefix("0x").removePrefix("0X"), 16)
+}
+
+/**
+ * Converts a string to its hexadecimal string representation with a "0x" prefix.
+ *
+ * @param string The string to convert.
+ * @return The hexadecimal string representation of the input string with a "0x" prefix.
+ */
+fun stringToHex(string: String): String {
+    return bytesToHex(string.toByteArray())
+}
+
+/**
+ * Converts a byte array to its hexadecimal string representation with a "0x" prefix.
+ *
+ * @param bytes The byte array to convert.
+ * @return The hexadecimal string representation of the byte array with a "0x" prefix.
+ */
+fun bytesToHex(bytes: ByteArray): String {
+    return "0x${bytes.joinToString("") { String.format("%02x", it) }}"
+}
+
+/**
+ * Converts a hexadecimal string to a Long.
+ *
+ * @param hex The hexadecimal string to convert.
+ * @return The Long representation of the hexadecimal string.
+ */
+fun hexToLong(hex: String): Long {
+    return hex.removePrefix("0x").removePrefix("0X").toLong(16)
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/encoding/ToBytesUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/encoding/ToBytesUtils.kt
new file mode 100644
index 0000000..99050e6
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/encoding/ToBytesUtils.kt
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.encoding
+
+import com.circle.modularwallets.core.utils.data.isHex
+import org.web3j.crypto.Hash
+import org.web3j.utils.Numeric
+import java.nio.charset.StandardCharsets
+
+/**
+ * Converts a string to a byte array.
+ *
+ * @param value The string to convert. If the string is a hexadecimal string, it will be converted to a byte array accordingly.
+ * @return The byte array representation of the input string.
+ */
+fun toBytes(value: String): ByteArray {
+    if(isHex(value)) {
+        return Numeric.hexStringToByteArray(value)
+    }
+    return value.toByteArray()
+}
+
+/**
+ * Computes the SHA-3 (Keccak-256) hash of the given message and returns it as a byte array.
+ *
+ * @param message The message to hash. If the message is a hexadecimal string, it will be converted to a byte array before hashing.
+ * @return The SHA-3 hash of the input message as a byte array.
+ */
+fun toSha3Bytes(message: String): ByteArray {
+    val digest = if(isHex(message)) {
+        Hash.sha3(Numeric.hexStringToByteArray(message))
+    } else {
+        Hash.sha3(message.toByteArray(StandardCharsets.UTF_8))
+    }
+    return digest
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/error/GetBundlerErrorUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/error/GetBundlerErrorUtils.kt
new file mode 100644
index 0000000..1e37a8d
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/error/GetBundlerErrorUtils.kt
@@ -0,0 +1,285 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.error
+
+import com.circle.modularwallets.core.errors.AccountNotDeployedError
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.errors.ExecutionRevertedError
+import com.circle.modularwallets.core.errors.FailedToSendToBeneficiaryError
+import com.circle.modularwallets.core.errors.GasValuesOverflowError
+import com.circle.modularwallets.core.errors.HandleOpsOutOfGasError
+import com.circle.modularwallets.core.errors.InitCodeFailedError
+import com.circle.modularwallets.core.errors.InitCodeMustCreateSenderError
+import com.circle.modularwallets.core.errors.InitCodeMustReturnSenderError
+import com.circle.modularwallets.core.errors.InsufficientPrefundError
+import com.circle.modularwallets.core.errors.InternalCallOnlyError
+import com.circle.modularwallets.core.errors.InvalidAccountNonceError
+import com.circle.modularwallets.core.errors.InvalidAggregatorError
+import com.circle.modularwallets.core.errors.InvalidBeneficiaryError
+import com.circle.modularwallets.core.errors.InvalidFieldsError
+import com.circle.modularwallets.core.errors.InvalidPaymasterAndDataError
+import com.circle.modularwallets.core.errors.PaymasterDepositTooLowError
+import com.circle.modularwallets.core.errors.PaymasterFunctionRevertedError
+import com.circle.modularwallets.core.errors.PaymasterNotDeployedError
+import com.circle.modularwallets.core.errors.PaymasterPostOpFunctionRevertedError
+import com.circle.modularwallets.core.errors.PaymasterRateLimitError
+import com.circle.modularwallets.core.errors.PaymasterStakeTooLowError
+import com.circle.modularwallets.core.errors.RpcRequestError
+import com.circle.modularwallets.core.errors.SenderAlreadyConstructedError
+import com.circle.modularwallets.core.errors.SignatureCheckFailedError
+import com.circle.modularwallets.core.errors.SmartAccountFunctionRevertedError
+import com.circle.modularwallets.core.errors.UnknownBundlerError
+import com.circle.modularwallets.core.errors.UnsupportedSignatureAggregatorError
+import com.circle.modularwallets.core.errors.UserOperationExpiredError
+import com.circle.modularwallets.core.errors.UserOperationOutOfTimeRangeError
+import com.circle.modularwallets.core.errors.UserOperationPaymasterExpiredError
+import com.circle.modularwallets.core.errors.UserOperationPaymasterSignatureError
+import com.circle.modularwallets.core.errors.UserOperationRejectedByEntryPointError
+import com.circle.modularwallets.core.errors.UserOperationRejectedByOpCodeError
+import com.circle.modularwallets.core.errors.UserOperationRejectedByPaymasterError
+import com.circle.modularwallets.core.errors.UserOperationSignatureError
+import com.circle.modularwallets.core.errors.VerificationGasLimitExceededError
+import com.circle.modularwallets.core.errors.VerificationGasLimitTooLowError
+import com.circle.modularwallets.core.models.UserOperationRpc
+import com.circle.modularwallets.core.utils.encoding.hexToBigInteger
+
+private val bundlerErrors = listOf(
+    ExecutionRevertedError(),
+    InvalidFieldsError(),
+    PaymasterDepositTooLowError(),
+    PaymasterRateLimitError(),
+    PaymasterStakeTooLowError(),
+    SignatureCheckFailedError(),
+    UnsupportedSignatureAggregatorError(),
+    UserOperationOutOfTimeRangeError(),
+    UserOperationRejectedByEntryPointError(),
+    UserOperationRejectedByPaymasterError(),
+    UserOperationRejectedByOpCodeError(),
+)
+
+internal fun getBundlerError(
+    err: BaseError,
+    args: UserOperationRpc?
+): BaseError {
+    val message = (err.details ?: "").lowercase()
+    val firstResult = when {
+        AccountNotDeployedError.message.toRegex().containsMatchIn(message) -> {
+            AccountNotDeployedError(cause = err)
+        }
+
+        FailedToSendToBeneficiaryError.message.toRegex().containsMatchIn(message) -> {
+            FailedToSendToBeneficiaryError(cause = err)
+        }
+
+        GasValuesOverflowError.message.toRegex().containsMatchIn(message) -> {
+            GasValuesOverflowError(cause = err)
+        }
+
+        HandleOpsOutOfGasError.message.toRegex().containsMatchIn(message) -> {
+            HandleOpsOutOfGasError(cause = err)
+        }
+
+        InitCodeFailedError.message.toRegex().containsMatchIn(message) -> {
+            InitCodeFailedError(
+                cause = err,
+                factory = args?.factory,
+                factoryData = args?.factoryData,
+                initCode = args?.initCode
+            )
+        }
+
+        InitCodeMustCreateSenderError.message.toRegex().containsMatchIn(message) -> {
+            InitCodeMustCreateSenderError(
+                cause = err,
+                factory = args?.factory,
+                factoryData = args?.factoryData,
+                initCode = args?.initCode
+            )
+        }
+
+        InitCodeMustReturnSenderError.message.toRegex().containsMatchIn(message) -> {
+            InitCodeMustReturnSenderError(
+                err,
+                factory = args?.factory,
+                factoryData = args?.factoryData,
+                initCode = args?.initCode,
+                sender = args?.sender
+            )
+        }
+
+
+        InsufficientPrefundError.message.toRegex().containsMatchIn(message) -> {
+            InsufficientPrefundError(cause = err)
+        }
+
+        InternalCallOnlyError.message.toRegex().containsMatchIn(message) -> {
+            InternalCallOnlyError(cause = err)
+        }
+
+        InvalidAccountNonceError.message.toRegex().containsMatchIn(message) -> {
+            InvalidAccountNonceError(
+                err,
+                nonce = hexToBigInteger(args?.nonce)
+            )
+        }
+
+        InvalidAggregatorError.message.toRegex().containsMatchIn(message) -> {
+            InvalidAggregatorError(cause = err)
+        }
+
+        InvalidBeneficiaryError.message.toRegex().containsMatchIn(message) -> {
+            InvalidBeneficiaryError(cause = err)
+        }
+
+        InvalidPaymasterAndDataError.message.toRegex().containsMatchIn(message) -> {
+            InvalidPaymasterAndDataError(cause = err)
+        }
+
+        PaymasterDepositTooLowError.message.toRegex().containsMatchIn(message) -> {
+            PaymasterDepositTooLowError(cause = err)
+        }
+
+        PaymasterFunctionRevertedError.message.toRegex().containsMatchIn(message) -> {
+            PaymasterFunctionRevertedError(cause = err)
+        }
+
+        PaymasterNotDeployedError.message.toRegex().containsMatchIn(message) -> {
+            PaymasterNotDeployedError(cause = err)
+        }
+
+        PaymasterPostOpFunctionRevertedError.message.toRegex().containsMatchIn(message) -> {
+            PaymasterPostOpFunctionRevertedError(cause = err)
+        }
+
+        SmartAccountFunctionRevertedError.message.toRegex().containsMatchIn(message) -> {
+            SmartAccountFunctionRevertedError(cause = err)
+        }
+
+        SenderAlreadyConstructedError.message.toRegex().containsMatchIn(message) -> {
+            SenderAlreadyConstructedError(
+                cause = err,
+                factory = args?.factory,
+                factoryData = args?.factoryData,
+                initCode = args?.initCode
+            )
+        }
+
+        UserOperationExpiredError.message.toRegex().containsMatchIn(message) -> {
+            UserOperationExpiredError(cause = err)
+        }
+
+        UserOperationPaymasterExpiredError.message.toRegex().containsMatchIn(message) -> {
+            UserOperationPaymasterExpiredError(cause = err)
+        }
+
+        UserOperationPaymasterSignatureError.message.toRegex().containsMatchIn(message) -> {
+            UserOperationPaymasterSignatureError(cause = err)
+        }
+
+        UserOperationSignatureError.message.toRegex().containsMatchIn(message) -> {
+            UserOperationSignatureError(cause = err)
+        }
+
+        VerificationGasLimitExceededError.message.toRegex().containsMatchIn(message) -> {
+            VerificationGasLimitExceededError(cause = err)
+        }
+
+        VerificationGasLimitTooLowError.message.toRegex().containsMatchIn(message) -> {
+            VerificationGasLimitTooLowError(cause = err)
+        }
+
+        else -> null
+    }
+
+    if (firstResult != null) {
+        return firstResult
+    }
+
+    if (err is RpcRequestError) {
+        val rpcErrorCode = err.code
+        val secondResult = bundlerErrors.firstOrNull { error ->
+            when (error) {
+                is ExecutionRevertedError -> ExecutionRevertedError.code == rpcErrorCode
+                is InvalidFieldsError -> InvalidFieldsError.code == rpcErrorCode
+                is PaymasterDepositTooLowError -> PaymasterDepositTooLowError.code == rpcErrorCode
+                is PaymasterRateLimitError -> PaymasterRateLimitError.code == rpcErrorCode
+                is PaymasterStakeTooLowError -> PaymasterStakeTooLowError.code == rpcErrorCode
+                is SignatureCheckFailedError -> SignatureCheckFailedError.code == rpcErrorCode
+                is UnsupportedSignatureAggregatorError -> UnsupportedSignatureAggregatorError.code == rpcErrorCode
+                is UserOperationOutOfTimeRangeError -> UserOperationOutOfTimeRangeError.code == rpcErrorCode
+                is UserOperationRejectedByEntryPointError -> UserOperationRejectedByEntryPointError.code == rpcErrorCode
+                is UserOperationRejectedByPaymasterError -> UserOperationRejectedByPaymasterError.code == rpcErrorCode
+                is UserOperationRejectedByOpCodeError -> UserOperationRejectedByOpCodeError.code == rpcErrorCode
+                else -> false
+            }
+        }
+        if (secondResult != null) {
+            when (secondResult) {
+                is ExecutionRevertedError -> {
+                    return ExecutionRevertedError(
+                        cause = err,
+                        message = err.details
+                    )
+                }
+
+                is InvalidFieldsError -> {
+                    return InvalidFieldsError(cause = err)
+                }
+
+                is PaymasterDepositTooLowError -> {
+                    return PaymasterDepositTooLowError(cause = err)
+                }
+
+                is PaymasterRateLimitError -> {
+                    return PaymasterRateLimitError(cause = err)
+                }
+
+                is PaymasterStakeTooLowError -> {
+                    return PaymasterStakeTooLowError(cause = err)
+                }
+
+                is SignatureCheckFailedError -> {
+                    return SignatureCheckFailedError(cause = err)
+                }
+
+                is UnsupportedSignatureAggregatorError -> {
+                    return UnsupportedSignatureAggregatorError(cause = err)
+                }
+
+                is UserOperationOutOfTimeRangeError -> {
+                    return UserOperationOutOfTimeRangeError(cause = err)
+                }
+
+                is UserOperationRejectedByEntryPointError -> {
+                    return UserOperationRejectedByEntryPointError(cause = err)
+                }
+
+                is UserOperationRejectedByPaymasterError -> {
+                    return UserOperationRejectedByPaymasterError(cause = err)
+                }
+
+                is UserOperationRejectedByOpCodeError -> {
+                    return UserOperationRejectedByOpCodeError(cause = err)
+                }
+            }
+        }
+    }
+
+    return UnknownBundlerError(err)
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/error/GetUserOperationErrorUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/error/GetUserOperationErrorUtils.kt
new file mode 100644
index 0000000..8f6910f
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/error/GetUserOperationErrorUtils.kt
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.error
+
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.errors.UserOperationExecutionError
+import com.circle.modularwallets.core.models.UserOperationRpc
+import com.circle.modularwallets.core.models.UserOperationV07
+import com.circle.modularwallets.core.models.toUserOperationV07
+
+internal fun getUserOperationError(
+    err: BaseError,
+    args: UserOperationRpc?,
+): BaseError {
+    val cause = getBundlerError(err, args)
+    return UserOperationExecutionError(
+        cause = cause,
+        userOp = args?.toUserOperationV07() ?: UserOperationV07() //use empty as default
+    )
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/rpc/ReqRespUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/rpc/ReqRespUtils.kt
new file mode 100644
index 0000000..7f5de00
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/rpc/ReqRespUtils.kt
@@ -0,0 +1,222 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.utils.rpc
+
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.errors.BaseErrorParameters
+import com.circle.modularwallets.core.errors.ChainDisconnectedError
+import com.circle.modularwallets.core.errors.HttpRequestError
+import com.circle.modularwallets.core.errors.InternalRpcError
+import com.circle.modularwallets.core.errors.InvalidInputRpcError
+import com.circle.modularwallets.core.errors.InvalidParamsRpcError
+import com.circle.modularwallets.core.errors.InvalidRequestRpcError
+import com.circle.modularwallets.core.errors.JsonRpcVersionUnsupportedError
+import com.circle.modularwallets.core.errors.LimitExceededRpcError
+import com.circle.modularwallets.core.errors.MethodNotFoundRpcError
+import com.circle.modularwallets.core.errors.MethodNotSupportedRpcError
+import com.circle.modularwallets.core.errors.ParseRpcError
+import com.circle.modularwallets.core.errors.ProviderDisconnectedError
+import com.circle.modularwallets.core.errors.ResourceNotFoundRpcError
+import com.circle.modularwallets.core.errors.ResourceUnavailableRpcError
+import com.circle.modularwallets.core.errors.RpcError
+import com.circle.modularwallets.core.errors.RpcRequestError
+import com.circle.modularwallets.core.errors.SwitchChainError
+import com.circle.modularwallets.core.errors.TransactionRejectedRpcError
+import com.circle.modularwallets.core.errors.UnauthorizedProviderError
+import com.circle.modularwallets.core.errors.UnknownRpcError
+import com.circle.modularwallets.core.errors.UnsupportedProviderMethodError
+import com.circle.modularwallets.core.errors.UserRejectedRequestError
+import com.circle.modularwallets.core.transports.HttpError
+import com.circle.modularwallets.core.transports.RpcRequest
+import com.circle.modularwallets.core.transports.RpcResponse
+import com.circle.modularwallets.core.transports.Transport
+import com.circle.modularwallets.core.utils.Logger
+import com.circle.modularwallets.core.utils.fromJson
+import com.circle.modularwallets.core.utils.toJson
+import com.squareup.moshi.FromJson
+import com.squareup.moshi.JsonAdapter
+import com.squareup.moshi.Moshi
+import com.squareup.moshi.ToJson
+import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
+import okhttp3.Interceptor
+import okhttp3.Request
+import okhttp3.RequestBody
+import okhttp3.Response
+import okio.Buffer
+import java.math.BigDecimal
+import java.math.BigInteger
+
+
+internal fun <T> resultToTypeAndJson(result: Any, type: Class<T>): Pair<T, String> {
+    val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
+    val jsonAdapter = moshi.adapter(Map::class.java)
+    val jsonString = jsonAdapter.toJson(result as Map<*, *>?)
+    val adapter: JsonAdapter<T> = moshi.adapter(type)
+    val obj = adapter.fromJson(jsonString)
+    obj ?: throw BaseError("Failed to transform from json: $jsonString")
+    return Pair(obj, jsonString)
+}
+
+internal suspend fun <T> performJsonRpcRequest(
+    transport: Transport,
+    rpcReq: RpcRequest,
+    type: Class<T>,
+    notFoundError: BaseError? = null
+): Pair<T, String> {
+    val result = performJsonRpcRequest(transport, rpcReq, notFoundError)
+    return resultToTypeAndJson(result, type)
+}
+
+internal fun getRpcError(error: RpcRequestError): RpcError {
+    return when (error.code) {
+        ParseRpcError.code -> ParseRpcError(error)
+        InvalidRequestRpcError.code -> InvalidRequestRpcError(error)
+        MethodNotFoundRpcError.code -> MethodNotFoundRpcError(error)
+        InvalidParamsRpcError.code -> InvalidParamsRpcError(error)
+        InternalRpcError.code -> InternalRpcError(error)
+        InvalidInputRpcError.code -> InvalidInputRpcError(error)
+        ResourceNotFoundRpcError.code -> ResourceNotFoundRpcError(error)
+        ResourceUnavailableRpcError.code -> ResourceUnavailableRpcError(error)
+        TransactionRejectedRpcError.code -> TransactionRejectedRpcError(error)
+        MethodNotSupportedRpcError.code -> MethodNotSupportedRpcError(error)
+        LimitExceededRpcError.code -> LimitExceededRpcError(error)
+        JsonRpcVersionUnsupportedError.code -> JsonRpcVersionUnsupportedError(error)
+        // CAIP-25: User Rejected Error
+        // https://docs.walletconnect.com/2.0/specs/clients/sign/error-codes#rejected-caip-25
+        5000, UserRejectedRequestError.code -> UserRejectedRequestError(error)
+        UnauthorizedProviderError.code -> UnauthorizedProviderError(error)
+        UnsupportedProviderMethodError.code -> UnsupportedProviderMethodError(error)
+        ProviderDisconnectedError.code -> ProviderDisconnectedError(error)
+        ChainDisconnectedError.code -> ChainDisconnectedError(error)
+        SwitchChainError.code -> SwitchChainError(error)
+        else -> UnknownRpcError(error)
+    }
+}
+
+internal suspend fun performJsonRpcRequest(
+    transport: Transport,
+    rpcReq: RpcRequest,
+    notFoundError: BaseError? = null
+): Any {
+    val call = transport.request(rpcReq)
+    val body = call.body()
+    body?.error?.let {
+        val req = call.raw().request
+        val rpcRequestError= RpcRequestError(
+            getBodyString(req.body), it,
+            url = req.url.toString()
+        )
+        throw getRpcError(rpcRequestError)
+    }
+    return body?.result ?: throw notFoundError ?: BaseError(
+        "RPC result is null",
+        BaseErrorParameters(
+            metaMessages = mutableListOf(
+                "URL: ${call.raw().request.url}",
+                "Request body: ${toJson(getBodyString(call.raw().request.body))}"
+            )
+        )
+    )
+}
+
+internal fun getMoshi(): Moshi {
+    return Moshi.Builder()
+        .add(BigDecimalAdapter)
+        .add(BigIntegerAdapter)
+        .add(KotlinJsonAdapterFactory())
+        .build()
+}
+
+@ExcludeFromGeneratedCCReport
+internal object BigDecimalAdapter {
+    @FromJson
+    fun fromJson(string: String) = BigDecimal(string)
+
+    @ToJson
+    fun toJson(value: BigDecimal) = value.toString()
+}
+
+@ExcludeFromGeneratedCCReport
+internal object BigIntegerAdapter {
+    @FromJson
+    fun fromJson(string: String) = BigInteger(string)
+
+    @ToJson
+    fun toJson(value: BigInteger) = value.toString()
+}
+
+internal fun getBodyString(body: RequestBody?): String {
+    val buffer = Buffer()
+    body?.writeTo(buffer)
+    val plainText = buffer.readByteArray()
+    return String(plainText)
+}
+
+internal object ParseInterceptor : Interceptor {
+    private const val MAX_RETRIES = 3
+    private const val HTTP_TOO_MANY_REQUESTS = 429
+    override fun intercept(chain: Interceptor.Chain): Response {
+        val request: Request = chain.request()
+        var response: Response = chain.proceed(request)
+        if (response.isSuccessful) {
+            return response
+        }
+
+        var tryCount = 0
+        while (tryCount < MAX_RETRIES && (response.code == HTTP_TOO_MANY_REQUESTS || response.code in 500..599)) {
+            tryCount++
+            Thread.sleep(1000L * tryCount)
+            Logger.d("http", "Retrying request#$tryCount due to ${response.code} error")
+            response = chain.proceed(chain.request())
+            if (response.isSuccessful) {
+                return response
+            }
+        }
+
+        val responseBodyString = response.body?.string() ?: ""
+        val errorMessage: String?
+        try {
+            if (responseBodyString.contains("jsonrpc")) {
+                val data = fromJson(responseBodyString, RpcResponse::class.java)
+                errorMessage = data?.error?.message
+            } else {
+                val data: HttpError? = fromJson(responseBodyString, HttpError::class.java)
+                errorMessage = data?.error ?: data?.message
+            }
+        } catch (t: Throwable) {
+            throw HttpRequestError(
+                body = getBodyString(request.body),
+                cause = t,
+                details = "Receive error during parsing: $responseBodyString",
+                status = response.code,
+                headers = request.headers,
+                url = request.url.toString()
+            )
+        }
+        throw HttpRequestError(
+            body = getBodyString(request.body), // response.body?.string() can only be called once only,
+            details = errorMessage ?: "No error and no message: $responseBodyString",
+            status = response.code,
+            headers = request.headers,
+            url = request.url.toString()
+        )
+    }
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/rpc/RetrofitProviderUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/rpc/RetrofitProviderUtils.kt
new file mode 100644
index 0000000..b9feb2f
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/rpc/RetrofitProviderUtils.kt
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.rpc
+
+import android.content.Context
+import android.content.pm.PackageInfo
+import android.content.pm.PackageManager
+import com.circle.modularwallets.core.BuildConfig
+import java.security.MessageDigest
+
+internal fun getAppInfo(context: Context): String {
+    return "platform=android;version=${BuildConfig.version};package=${context.packageName};signature=${
+        getSha256CertificateFingerprint(
+            context
+        )
+    }"
+}
+
+internal fun getSha256CertificateFingerprint(context: Context): String? {
+    try {
+        val packageInfo: PackageInfo = context.packageManager.getPackageInfo(
+            context.packageName,
+            PackageManager.GET_SIGNING_CERTIFICATES
+        )
+        val signature = packageInfo.signingInfo.apkContentsSigners[0]
+
+        val messageDigest = MessageDigest.getInstance("SHA-256")
+        val digest = messageDigest.digest(signature.toByteArray())
+        val fingerprint = digest.joinToString(":") { String.format("%02X", it) }
+        return fingerprint
+    } catch (e: Exception) {
+        e.printStackTrace()
+        return null
+    }
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/signature/Base64UrlConversionUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/Base64UrlConversionUtils.kt
new file mode 100644
index 0000000..54ea091
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/Base64UrlConversionUtils.kt
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.signature
+
+import android.util.Base64
+import java.nio.charset.StandardCharsets
+
+internal fun base64UrlToBase64(base64Url: String): String {
+    return base64Url.replace('-', '+').replace('_', '/')
+}
+
+internal fun base64ToBase64Url(base64: String): String {
+    return base64.replace('+', '-')
+        .replace('/', '_')
+        .replace(Regex("=+$"), "")
+}
+
+internal fun base64UrlToBytes(base64Url: String): ByteArray {
+    val base64 = base64UrlToBase64(base64Url)
+    return Base64.decode(base64, Base64.DEFAULT)
+}
+
+internal fun bytesToBase64Url(bytes: ByteArray): String {
+    val base64 = Base64.encodeToString(bytes, Base64.DEFAULT)
+    return base64ToBase64Url(base64)
+}
+
+internal fun base64DecodeToString(strEncoded: String): String {
+    val decodedBytes = Base64.decode(strEncoded, Base64.URL_SAFE)
+    return String(decodedBytes, StandardCharsets.UTF_8)
+}
+
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/signature/HashMessageUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/HashMessageUtils.kt
new file mode 100644
index 0000000..21e0d60
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/HashMessageUtils.kt
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.signature
+
+import com.circle.modularwallets.core.utils.encoding.bytesToHex
+import com.circle.modularwallets.core.utils.encoding.toBytes
+import org.web3j.crypto.Sign
+import org.web3j.utils.Numeric
+
+/**
+ * Hashes the given hex string using Ethereum's message hash algorithm.
+ *
+ * @param hex The hex string to hash.
+ * @return The hashed message as a hex string.
+ */
+fun hashMessage(hex: String): String {
+    val bytes = toBytes(hex)
+    return hashMessage(bytes)
+}
+
+/**
+ * Hashes the given byte array using Ethereum's message hash algorithm.
+ *
+ * @param byteArray The byte array to hash.
+ * @return The hashed message as a hex string.
+ */
+fun hashMessage(byteArray: ByteArray): String {
+    return bytesToHex(Sign.getEthereumMessageHash(byteArray))
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/signature/HashTypedDataUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/HashTypedDataUtils.kt
new file mode 100644
index 0000000..87d2a9d
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/HashTypedDataUtils.kt
@@ -0,0 +1,68 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.signature
+
+import com.circle.modularwallets.core.models.EIP712Domain
+import com.circle.modularwallets.core.models.EIP712Message
+import com.circle.modularwallets.core.models.Entry
+import com.circle.modularwallets.core.utils.encoding.bytesToHex
+import com.circle.modularwallets.core.utils.signature.StructuredDataEncoder.Companion.parseJSONMessage
+
+/**
+ * Hashes the given typed data using the EIP-712 standard.
+ *
+ * @param jsonData The JSON string representing the typed data.
+ * @param overrideData Optional EIP-712 message to override the parsed JSON data.
+ * @return The hashed typed data as a hex string.
+ */
+
+@JvmOverloads
+@Throws(Exception::class)
+fun hashTypedData(jsonData: String, overrideData: EIP712Message? = null): String {
+    val typedData = parseJSONMessage(jsonData)
+    overrideData?.types?.let {
+        typedData.types = it
+    }
+    overrideData?.primaryType?.let {
+        typedData.primaryType = it
+    }
+    overrideData?.message?.let {
+        typedData.message = it
+    }
+    overrideData?.domain?.let {
+        typedData.domain = it
+    }
+
+    typedData.types?.put("EIP712Domain", getTypesForEIP712Domain(typedData.domain))
+
+    val dataEncoder = StructuredDataEncoder(typedData)
+    val hashStructuredData = dataEncoder.hashStructuredData()
+    return bytesToHex(hashStructuredData)
+}
+
+internal fun getTypesForEIP712Domain(domain: EIP712Domain?): MutableList<Entry> {
+    val types = mutableListOf<Entry>()
+    domain?.name?.let { types.add(Entry("name", "string")) }
+    domain?.version?.let { types.add(Entry("version", "string")) }
+    domain?.chainId?.let { types.add(Entry("chainId", "uint256")) }
+    domain?.verifyingContract?.let { types.add(Entry("verifyingContract", "address")) }
+    domain?.salt?.let { types.add(Entry("salt", "bytes32")) }
+    return types
+}
+
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/signature/PublicKeyConversionUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/PublicKeyConversionUtils.kt
new file mode 100644
index 0000000..7ebbc4b
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/PublicKeyConversionUtils.kt
@@ -0,0 +1,105 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.signature
+
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.utils.encoding.bytesToHex
+import com.circle.modularwallets.core.utils.encoding.hexToBigInteger
+import org.web3j.utils.Numeric.hexStringToByteArray
+import java.math.BigInteger
+import java.security.KeyFactory
+import java.security.PublicKey
+import java.security.interfaces.ECPublicKey
+import java.security.spec.ECFieldFp
+import java.security.spec.ECParameterSpec
+import java.security.spec.ECPoint
+import java.security.spec.ECPublicKeySpec
+import java.security.spec.EllipticCurve
+import java.security.spec.X509EncodedKeySpec
+
+internal fun parseCredentialPublicKey(cPublicKey: String): ECPublicKey {
+    val bytes = base64UrlToBytes(cPublicKey)
+    val publicKey = toECPublicKey(bytes)
+    return publicKey
+}
+
+internal fun toECPublicKey(bytes: ByteArray): ECPublicKey {
+    val keySpec = X509EncodedKeySpec(bytes)
+    val keyFactory = KeyFactory.getInstance("EC")
+    val publicKey = keyFactory.generatePublic(keySpec)
+    if (publicKey !is ECPublicKey) {
+        throw BaseError("PublicKey is not of type ECPublicKey")
+    }
+    return publicKey
+}
+
+internal fun parsePublicKey(hexString: String): ECPublicKey {
+    val (x, y) = parseP256Signature(hexString)
+    /**
+     * References for p, a, b, gx, gy, n:
+     * https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf, p.101
+     * https://www.secg.org/sec2-v2.pdf, p.14
+     * */
+    val p = BigInteger("115792089210356248762697446949407573530086143415290314195533631308867097853951")
+    val a = BigInteger("FFFFFFFF00000001000000000000000000000000FFFFFFFFFFFFFFFFFFFFFFFC", 16)
+    val b = BigInteger("5ac635d8aa3a93e7b3ebbd55769886bc651d06b0cc53b0f63bce3c3e27d2604b", 16)
+    val gx = BigInteger("6b17d1f2e12c4247f8bce6e563a440f277037d812deb33a0f4a13945d898c296", 16)
+    val gy = BigInteger("4fe342e2fe1a7f9b8ee7eb4a7c0f9e162bce33576b315ececbb6406837bf51f5", 16)
+    val n = BigInteger("115792089210356248762697446949407573529996955224135760342422259061068512044369")
+
+    val curve = EllipticCurve(ECFieldFp(p), a, b)
+    val g = ECPoint(gx, gy)
+    val ecParameterSpec = ECParameterSpec(curve, g, n, 1)
+
+    val ecPoint = ECPoint(x, y)
+    val keySpec = ECPublicKeySpec(ecPoint, ecParameterSpec)
+
+    val keyFactory = KeyFactory.getInstance("EC")
+    return keyFactory.generatePublic(keySpec) as ECPublicKey
+}
+
+internal fun parseP256Signature(hex: String): Pair<BigInteger, BigInteger> {
+    val xy = parseP256SignatureToBytes(hex)
+    return Pair(hexToBigInteger(bytesToHex(xy.first))!!, hexToBigInteger(bytesToHex(xy.second))!!)
+}
+
+internal fun parseP256SignatureToBytes(hex: String): Pair<ByteArray, ByteArray> {
+    // xy for public key, rs for signature
+    val bytes = hexStringToByteArray(hex)
+    val offset = if (bytes.size == 65) 1 else 0
+
+    val x = bytes.copyOfRange(offset, 32 + offset)
+    val y = bytes.copyOfRange(32 + offset, 64 + offset)
+
+    return Pair(x, y)
+}
+
+internal fun serializePublicKey(publicKey: ECPublicKey): String {
+    val point = publicKey.w
+    val x = hexToBigInteger(bytesToHex(point.affineX.toByteArray())) ?: throw BaseError("x is null")
+    val y = hexToBigInteger(bytesToHex(point.affineY.toByteArray())) ?: throw BaseError("y is null")
+    return serializePublicKey(x, y)
+}
+
+internal fun serializePublicKey(x: BigInteger, y: BigInteger): String {
+    val result = mutableListOf<Byte>()
+    result.addAll(numberToBytesBE(x, 32).toList())
+    result.addAll(numberToBytesBE(y, 32).toList())
+    return bytesToHex(result.toByteArray())
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/signature/SignatureConversionUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/SignatureConversionUtils.kt
new file mode 100644
index 0000000..2ee1bbc
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/SignatureConversionUtils.kt
@@ -0,0 +1,105 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.signature
+
+
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.errors.BaseErrorParameters
+import com.circle.modularwallets.core.utils.encoding.bytesToHex
+import org.bouncycastle.asn1.ASN1InputStream
+import org.bouncycastle.asn1.ASN1Integer
+import org.bouncycastle.asn1.DERSequenceGenerator
+import org.bouncycastle.asn1.DLSequence
+import org.web3j.crypto.ECDSASignature
+import org.web3j.utils.Numeric.hexStringToByteArray
+import java.io.ByteArrayOutputStream
+import java.io.IOException
+import java.math.BigInteger
+
+
+internal val P256_N = BigInteger("FFFFFFFF00000000FFFFFFFFFFFFFFFFBCE6FAADA7179E84F3B9CAC2FC632551", 16)
+internal val P256_N_DIV_2 = P256_N.shiftRight(1)
+
+internal fun adjustSignature(r: BigInteger, s: BigInteger): Pair<BigInteger, BigInteger> {
+    return if (s > P256_N_DIV_2) {
+        Pair(r, P256_N - s)
+    } else {
+        Pair(r, s)
+    }
+}
+
+internal fun parseAsn1Signature(signature: String): ECDSASignature {
+    val ecdsaSignature = fromDerFormat(base64UrlToBytes(signature))
+    return ecdsaSignature
+}
+
+internal fun fromDerFormat(bytes: ByteArray?): ECDSASignature {
+    try {
+        ASN1InputStream(bytes).use { decoder ->
+            val seq: DLSequence = decoder.readObject() as DLSequence
+            val r: ASN1Integer
+            val s: ASN1Integer
+            try {
+                r = seq.getObjectAt(0) as ASN1Integer
+                s = seq.getObjectAt(1) as ASN1Integer
+            } catch (e: ClassCastException) {
+                throw BaseError("Invalid signature format", BaseErrorParameters(cause = e))
+            }
+            return ECDSASignature(r.positiveValue, s.positiveValue)
+        }
+    } catch (e: IOException) {
+        throw BaseError("Invalid signature format", BaseErrorParameters(cause = e))
+    }
+}
+
+internal fun parseSignature(hexSignature: String): String {
+    val (r, s) = parseP256Signature(hexSignature)
+    val esdsaSignature = ECDSASignature(r, s)
+    val bytes = toDerFormat(esdsaSignature)
+    return bytesToBase64Url(bytes).replace("\n", "")
+}
+
+internal fun toDerFormat(signature: ECDSASignature): ByteArray {
+    try {
+        ByteArrayOutputStream().use { baos ->
+            val seq: DERSequenceGenerator = DERSequenceGenerator(baos)
+            seq.addObject(ASN1Integer(signature.r))
+            seq.addObject(ASN1Integer(signature.s))
+            seq.close()
+            return baos.toByteArray()
+        }
+    } catch (ex: IOException) {
+        return ByteArray(0)
+    }
+}
+
+internal fun serializeSignature(r: BigInteger, s: BigInteger): String {
+    val result = ByteArray(64).apply {
+        val rBytes = numberToBytesBE(r, 32)
+        val sBytes = numberToBytesBE(s, 32)
+        System.arraycopy(rBytes, 0, this, 0, rBytes.size)
+        System.arraycopy(sBytes, 0, this, rBytes.size, sBytes.size)
+    }
+    return bytesToHex(result)
+}
+
+internal fun numberToBytesBE(n: BigInteger, len: Int): ByteArray {
+    val hex = n.toString(16).padStart(len * 2, '0')
+    return hexStringToByteArray(hex)
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/signature/StructuredDataEncoder.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/StructuredDataEncoder.kt
new file mode 100644
index 0000000..e177cf5
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/StructuredDataEncoder.kt
@@ -0,0 +1,558 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.signature
+
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.models.EIP712Message
+import com.circle.modularwallets.core.models.Entry
+import com.fasterxml.jackson.databind.ObjectMapper
+import org.web3j.abi.TypeEncoder
+import org.web3j.abi.datatypes.AbiTypes
+import org.web3j.crypto.Hash
+import org.web3j.crypto.Pair
+import org.web3j.utils.Numeric
+import java.io.ByteArrayOutputStream
+import java.lang.reflect.InvocationTargetException
+import java.math.BigInteger
+import java.util.Locale
+import java.util.TreeSet
+import java.util.function.Function
+import java.util.regex.Pattern
+import java.util.stream.Collectors
+
+internal class StructuredDataEncoder(val jsonMessageObject: EIP712Message) {
+
+    internal companion object {
+        // Matches array declarations like arr[5][10], arr[][], arr[][34][], etc.
+        // Doesn't match array declarations where there is a 0 in any dimension.
+        // Eg- arr[0][5] is not matched.
+        const val arrayTypeRegex: String = "^([a-zA-Z_$][a-zA-Z_$0-9]*)((\\[([1-9]\\d*)?\\])+)$"
+        val arrayTypePattern: Pattern = Pattern.compile(arrayTypeRegex)
+
+        const val bytesTypeRegex: String = "^bytes[0-9][0-9]?$"
+        val bytesTypePattern: Pattern = Pattern.compile(bytesTypeRegex)
+
+        // This regex tries to extract the dimensions from the
+        // square brackets of an array declaration using the ``Regex Groups``.
+        // Eg- It extracts ``5, 6, 7`` from ``[5][6][7]``
+        const val arrayDimensionRegex: String = "\\[([1-9]\\d*)?\\]"
+        val arrayDimensionPattern: Pattern = Pattern.compile(arrayDimensionRegex)
+
+        // Fields of Entry Objects need to follow a regex pattern
+        // Type Regex matches to a valid name or an array declaration.
+        const val typeRegex: String = "^[a-zA-Z_$][a-zA-Z_$0-9]*(\\[([1-9]\\d*)*\\])*$"
+        val typePattern: Pattern = Pattern.compile(typeRegex)
+
+        // Identifier Regex matches to a valid name, but can't be an array declaration.
+        const val identifierRegex: String = "^[a-zA-Z_$][a-zA-Z_$0-9]*$"
+        val identifierPattern: Pattern = Pattern.compile(identifierRegex)
+
+        fun parseJSONMessage(jsonMessageInString: String?): EIP712Message {
+            val mapper = ObjectMapper()
+            val tempJSONMessageObject =
+                mapper.readValue(jsonMessageInString, EIP712Message::class.java)
+            return tempJSONMessageObject
+        }
+
+        @Throws(java.lang.RuntimeException::class)
+        fun validateStructuredData(jsonMessageObject: EIP712Message) {
+            jsonMessageObject.types?.let {
+                for (structName in it.keys) {
+                    val fields: List<Entry> = it[structName] ?: continue
+                    for ((name, type) in fields) {
+                        if (name != null && !identifierPattern.matcher(name).find()) {
+                            // raise Error
+                            throw BaseError(
+                                String.format(
+                                    "Invalid Identifier %s in %s", name, structName
+                                )
+                            )
+                        }
+                        if (type != null && !typePattern.matcher(type).find()) {
+                            // raise Error
+                            throw BaseError(
+                                String.format("Invalid Type %s in %s", type, structName)
+                            )
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    fun getDependencies(primaryType: String): HashSet<String> {
+        // Find all the dependencies of a type
+        val deps = java.util.HashSet<String>()
+        val types: MutableMap<String, MutableList<Entry>> = jsonMessageObject.types ?: return deps
+
+        if (!types.containsKey(primaryType)) {
+            return deps
+        }
+
+        val remainingTypes: MutableList<String?> = ArrayList()
+        remainingTypes.add(primaryType)
+
+        while (remainingTypes.size > 0) {
+            val structName = remainingTypes[remainingTypes.size - 1] ?: continue
+            remainingTypes.removeAt(remainingTypes.size - 1)
+            deps.add(structName)
+
+            for ((_, type) in types[primaryType]!!) {
+                if (!types.containsKey(type)) {
+                    // Don't expand on non-user defined types
+                } else if (deps.contains(type)) {
+                    // Skip types which are already expanded
+                } else {
+                    // Encountered a user defined type
+                    remainingTypes.add(type)
+                }
+            }
+        }
+
+        return deps
+    }
+
+    fun encodeStruct(structName: String): String {
+        val types: MutableMap<String, MutableList<Entry>>? = jsonMessageObject.types
+
+        var structRepresentation = StringBuilder("$structName(")
+        for ((name, type) in types!![structName]!!) {
+            structRepresentation.append(String.format("%s %s,", type, name))
+        }
+        if (!types[structName].isNullOrEmpty()) {
+            structRepresentation =
+                StringBuilder(
+                    structRepresentation.substring(0, structRepresentation.length - 1)
+                )
+        }
+        structRepresentation.append(")")
+
+        return structRepresentation.toString()
+    }
+
+    fun encodeType(primaryType: String): String {
+        val deps = getDependencies(primaryType)
+        deps.remove(primaryType)
+
+        // Sort the other dependencies based on Alphabetical Order and finally add the primaryType
+        val depsAsList: MutableList<String> = mutableListOf()
+        depsAsList.addAll(deps.toList())
+        deps.sorted()
+        depsAsList.add(0, primaryType)
+
+        val result = java.lang.StringBuilder()
+        for (structName in depsAsList) {
+            result.append(encodeStruct(structName))
+        }
+
+        return result.toString()
+    }
+
+    fun typeHash(primaryType: String): ByteArray {
+        return Numeric.hexStringToByteArray(
+            Hash.sha3String(
+                encodeType(
+                    primaryType
+                )
+            )
+        )
+    }
+
+    fun getArrayDimensionsFromDeclaration(declaration: String?): List<Int> {
+        // Get the dimensions which were declared in Schema.
+        // If any dimension is empty, then it's value is set to -1.
+        val arrayTypeMatcher = arrayTypePattern.matcher(declaration ?: "")
+        arrayTypeMatcher.find()
+        val dimensionTypeMatcher = arrayDimensionPattern.matcher(declaration ?: "")
+        val dimensions: MutableList<Int> = java.util.ArrayList()
+        while (dimensionTypeMatcher.find()) {
+            val currentDimension = dimensionTypeMatcher.group(1)
+            if (currentDimension == null) {
+                dimensions.add("-1".toInt())
+            } else {
+                dimensions.add(currentDimension.toInt())
+            }
+        }
+
+        return dimensions
+    }
+
+    fun getDepthsAndDimensions(data: Any?, depth: Int): List<Pair> {
+        if (data !is List<*>) {
+            // Nothing more to recurse, since the data is no more an array
+            return emptyList()
+        }
+
+        val list: MutableList<Pair> = mutableListOf()
+        val dataAsArray = data.filterIsInstance<Any>()
+
+        list.add(Pair(depth, dataAsArray.size))
+        for (subdimensionalData in dataAsArray) {
+            list.addAll(getDepthsAndDimensions(subdimensionalData, depth + 1))
+        }
+
+        return list
+    }
+
+    @Throws(RuntimeException::class)
+    fun getArrayDimensionsFromData(data: Any?): List<Int> {
+        val depthsAndDimensions = getDepthsAndDimensions(data, 0)
+        // groupedByDepth has key as depth and value as List(pair(Depth, Dimension))
+        val groupedByDepth =
+            depthsAndDimensions.stream().collect(
+                Collectors.groupingBy(
+                    Function { obj: Pair -> obj.first })
+            )
+
+        // depthDimensionsMap is aimed to have key as depth and value as List(Dimension)
+        val depthDimensionsMap: MutableMap<Int, List<Int>> = HashMap()
+        for ((key, value) in groupedByDepth) {
+            val pureDimensions: MutableList<Int> = java.util.ArrayList()
+            for (depthDimensionPair in value) {
+                pureDimensions.add(depthDimensionPair.second as Int)
+            }
+            depthDimensionsMap[key as Int] = pureDimensions
+        }
+
+        val dimensions: MutableList<Int> = java.util.ArrayList()
+        for ((key, value) in depthDimensionsMap) {
+            val setOfDimensionsInParticularDepth: Set<Int> = TreeSet(
+                value
+            )
+            if (setOfDimensionsInParticularDepth.size != 1) {
+                throw BaseError(
+                    String.format(
+                        "Depth %d of array data has more than one dimensions",
+                        key
+                    )
+                )
+            }
+            dimensions.add(setOfDimensionsInParticularDepth.stream().findFirst().get())
+        }
+
+        return dimensions
+    }
+
+    fun flattenMultidimensionalArray(data: Any): List<Any> {
+        if (data !is List<*>) {
+            return ArrayList<Any>().apply { add(data) }
+        }
+
+        val flattenedArray = mutableListOf<Any>()
+        for (arrayItem in data) {
+            arrayItem?.let {
+                flattenedArray.addAll(flattenMultidimensionalArray(arrayItem))
+            }
+        }
+
+        return flattenedArray
+    }
+
+    private fun convertToEncodedItem(baseType: String, data: Any): ByteArray {
+        var hashBytes: ByteArray
+        try {
+            if (baseType.lowercase(Locale.getDefault()).startsWith("uint")
+                || baseType.lowercase(Locale.getDefault()).startsWith("int")
+            ) {
+                hashBytes = convertToBigInt(data).toByteArray()
+            } else if (baseType == "string") {
+                hashBytes = (data as String).toByteArray()
+            } else if (baseType == "bytes") {
+                hashBytes = Numeric.hexStringToByteArray(data as String)
+            } else {
+                val b = convertArgToBytes(data as String)
+                val bi = BigInteger(1, b)
+                hashBytes = Numeric.toBytesPadded(bi, 32)
+            }
+        } catch (e: Exception) {
+            e.printStackTrace()
+            hashBytes = ByteArray(0)
+        }
+
+        return hashBytes
+    }
+
+    @Throws(NumberFormatException::class, NullPointerException::class)
+    private fun convertToBigInt(value: Any): BigInteger {
+        return if (value.toString().startsWith("0x")) {
+            Numeric.toBigInt(value.toString())
+        } else {
+            BigInteger(value.toString())
+        }
+    }
+
+    @Throws(java.lang.Exception::class)
+    private fun convertArgToBytes(inputValue: String): ByteArray {
+        var hexValue = inputValue
+        if (!Numeric.containsHexPrefix(inputValue)) {
+            val value = try {
+                BigInteger(inputValue)
+            } catch (e: java.lang.NumberFormatException) {
+                BigInteger(inputValue, 16)
+            }
+
+            hexValue = Numeric.toHexStringNoPrefix(value.toByteArray())
+            // fix sign condition
+            if (hexValue.length > 64 && hexValue.startsWith("00")) {
+                hexValue = hexValue.substring(2)
+            }
+        }
+
+        return Numeric.hexStringToByteArray(hexValue)
+    }
+
+    private fun getArrayItems(field: Entry, value: Any): List<Any> {
+        val expectedDimensions = getArrayDimensionsFromDeclaration(field.type)
+        // This function will itself give out errors in case
+        // that the data is not a proper array
+        val dataDimensions = getArrayDimensionsFromData(value)
+
+        val format = String.format(
+            "Array Data %s has dimensions %s, " + "but expected dimensions are %s",
+            value.toString(), dataDimensions.toString(), expectedDimensions.toString()
+        )
+        if (expectedDimensions.size != dataDimensions.size) {
+            // Ex: Expected a 3d array, but got only a 2d array
+            throw BaseError(format)
+        }
+        for (i in expectedDimensions.indices) {
+            if (expectedDimensions[i] == -1) {
+                // Skip empty or dynamically declared dimensions
+                continue
+            }
+            if (expectedDimensions[i] != dataDimensions[i]) {
+                throw BaseError(format)
+            }
+        }
+
+        return flattenMultidimensionalArray(value)
+    }
+
+    @Throws(java.lang.RuntimeException::class)
+    fun encodeData(primaryType: String, data: Map<String, Any>): ByteArray {
+        val types: MutableMap<String, MutableList<Entry>> =
+            jsonMessageObject.types ?: return ByteArrayOutputStream().toByteArray()
+
+        val encTypes: MutableList<String> = mutableListOf()
+        val encValues: MutableList<Any> = mutableListOf()
+
+        // Add typehash
+        encTypes.add("bytes32")
+        encValues.add(typeHash(primaryType))
+
+        types[primaryType]?.let {
+            // Add field contents
+            for (field in it) {
+                val value = data[field.name] ?: continue
+                val fieldType = field.type ?: continue
+                if (fieldType == "string") {
+                    encTypes.add("bytes32")
+                    val hashedValue = Numeric.hexStringToByteArray(Hash.sha3String(value as String))
+                    encValues.add(hashedValue)
+                } else if (fieldType == "bytes") {
+                    encTypes.add(("bytes32"))
+                    encValues.add(Hash.sha3(Numeric.hexStringToByteArray(value as String)))
+                } else if (types.containsKey(fieldType)) {
+                    if (value is Map<*, *>) {
+                        val safeMap = value.mapKeys {
+                            if (it.key !is String) {
+                                throw BaseError("Invalid key type: Expected String but got ${it.key?.javaClass}")
+                            }
+                            it.key as String
+                        }.mapValues {
+                            if (it.value == null) {
+                                throw BaseError("Invalid value: Expected non-null Any but got null for key ${it.key}")
+                            }
+                            it.value as Any
+                        }
+
+                        val hashedValue = Hash.sha3(encodeData(fieldType, safeMap))
+                        encTypes.add("bytes32")
+                        encValues.add(hashedValue)
+                    } else {
+                        throw BaseError("Expected a Map<String, Any> but got ${value.javaClass}")
+                    }
+                } else if (bytesTypePattern.matcher(fieldType).find()) {
+                    encTypes.add(fieldType)
+                    encValues.add(Numeric.hexStringToByteArray(value as String))
+                } else if (arrayTypePattern.matcher(fieldType).find()) {
+                    val baseTypeName = fieldType.substring(0, fieldType.indexOf('['))
+                    val arrayItems = getArrayItems(field, value)
+                    val concatenatedArrayEncodingBuffer = ByteArrayOutputStream()
+
+                    for (arrayItem in arrayItems) {
+                        val arrayItemEncoding = if (types.containsKey(baseTypeName)) {
+                            val safeMap = safeCastToMap(arrayItem)
+                            Hash.sha3(encodeData(baseTypeName, safeMap))
+                        } else {
+                            convertToEncodedItem(
+                                baseTypeName,
+                                arrayItem
+                            ) // add raw item, packed to 32 bytes
+                        }
+
+                        concatenatedArrayEncodingBuffer.write(
+                            arrayItemEncoding, 0, arrayItemEncoding.size
+                        )
+                    }
+
+                    val concatenatedArrayEncodings = concatenatedArrayEncodingBuffer.toByteArray()
+                    val hashedValue = Hash.sha3(concatenatedArrayEncodings)
+                    encTypes.add("bytes32")
+                    encValues.add(hashedValue)
+                } else if (fieldType.startsWith("uint") || fieldType.startsWith("int")) {
+                    encTypes.add(fieldType)
+                    // convert to BigInteger for ABI constructor compatibility
+                    try {
+                        encValues.add(convertToBigInt(value))
+                    } catch (e: java.lang.NumberFormatException) {
+                        encValues.add(
+                            value
+                        ) // value null or failed to convert, fallback to add string as
+                        // before
+                    } catch (e: java.lang.NullPointerException) {
+                        encValues.add(
+                            value
+                        )
+                    }
+                } else {
+                    encTypes.add(fieldType)
+                    encValues.add(value)
+                }
+            }
+        }
+
+        val baos = ByteArrayOutputStream()
+        for (i in encTypes.indices) {
+            val typeClazz = AbiTypes.getType(encTypes[i])
+                ?: throw BaseError("Unsupported or invalid type ${encTypes[i]}")
+
+            var atleastOneConstructorExistsForGivenParametersType = false
+            // Using the Reflection API to get the types of the parameters
+            val constructors = typeClazz.constructors
+            for (constructor in constructors) {
+                // Check which constructor matches
+                try {
+                    val parameterTypes = constructor.parameterTypes
+                    val temp =
+                        Numeric.hexStringToByteArray(
+                            TypeEncoder.encode(
+                                typeClazz
+                                    .getDeclaredConstructor(*parameterTypes)
+                                    .newInstance(encValues[i])
+                            )
+                        )
+                    baos.write(temp, 0, temp.size)
+                    atleastOneConstructorExistsForGivenParametersType = true
+                    break
+                } catch (ignored: IllegalArgumentException) {
+                } catch (ignored: NoSuchMethodException) {
+                } catch (ignored: InstantiationException) {
+                } catch (ignored: IllegalAccessException) {
+                } catch (ignored: InvocationTargetException) {
+                }
+            }
+
+            if (!atleastOneConstructorExistsForGivenParametersType) {
+                throw BaseError(
+                    String.format(
+                        "Received an invalid argument for which no constructor"
+                                + " exists for the ABI Class %s",
+                        typeClazz.simpleName
+                    )
+                )
+            }
+        }
+
+        return baos.toByteArray()
+    }
+
+    fun safeCastToMap(arrayItem: Any) = if (arrayItem is Map<*, *>) {
+        arrayItem.mapKeys { entry ->
+            if (entry.key !is String) {
+                throw BaseError("Invalid key type: Expected String but got ${entry.key?.javaClass}")
+            }
+            entry.key as String
+        }.mapValues { entry ->
+            if (entry.value == null) {
+                throw BaseError("Invalid value: Expected non-null Any but got null for key ${entry.key}")
+            }
+            entry.value as Any
+        }
+    } else {
+        throw BaseError("Expected a Map<String, Any> but got ${arrayItem.javaClass}")
+    }
+
+    @Throws(java.lang.RuntimeException::class)
+    fun hashMessage(primaryType: String, data: MutableMap<String, Any>): ByteArray {
+        return Hash.sha3(encodeData(primaryType, data))
+    }
+
+    @Throws(java.lang.RuntimeException::class)
+    fun hashDomain(): ByteArray {
+        val data = hashMapOf<String, Any>()
+        jsonMessageObject.domain?.name?.let {
+            data.put("name", it)
+        }
+        jsonMessageObject.domain?.version?.let {
+            data.put("version", it)
+        }
+        jsonMessageObject.domain?.chainId?.let {
+            data.put("chainId", it)
+        }
+        jsonMessageObject.domain?.verifyingContract?.let {
+            data.put("verifyingContract", it)
+        }
+        jsonMessageObject.domain?.salt?.let {
+            data.put("salt", it)
+        }
+        return Hash.sha3(encodeData("EIP712Domain", data))
+    }
+
+    @Throws(java.lang.RuntimeException::class)
+    fun getStructuredData(): ByteArray {
+        val baos = ByteArrayOutputStream()
+
+        val messagePrefix = "\u0019\u0001"
+        val prefix = messagePrefix.toByteArray()
+        baos.write(prefix, 0, prefix.size)
+
+        val domainHash = hashDomain()
+        baos.write(domainHash, 0, domainHash.size)
+        if (jsonMessageObject.primaryType != "EIP712Domain" && jsonMessageObject.primaryType != null && jsonMessageObject.message != null) {
+            val dataHash =
+                hashMessage(
+                    jsonMessageObject.primaryType!!,
+                    jsonMessageObject.message!!
+                )
+            baos.write(dataHash, 0, dataHash.size)
+        }
+
+        return baos.toByteArray()
+    }
+
+    @Throws(java.lang.RuntimeException::class)
+    fun hashStructuredData(): ByteArray {
+        return Hash.sha3(getStructuredData())
+    }
+}
+
+
+// hashStructuredData > getStructuredData > hashDomain, hashMessage
+// > encodeData > typeHash > encodeType > getDependencies
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/signature/VerifyUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/VerifyUtils.kt
new file mode 100644
index 0000000..f4a1035
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/signature/VerifyUtils.kt
@@ -0,0 +1,110 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.utils.signature
+
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.circle.modularwallets.core.models.WebAuthnData
+import com.circle.modularwallets.core.utils.encoding.bytesToHex
+import org.web3j.utils.Numeric.hexStringToByteArray
+import java.security.MessageDigest
+import java.security.PublicKey
+import java.security.Signature
+
+@ExcludeFromGeneratedCCReport
+internal fun verifyBasic(
+    hash: String,
+    authenticatorDataBytes: ByteArray,
+    webAuthn: WebAuthnData
+): Boolean {
+    // Check length of `authenticatorData`.
+    if (authenticatorDataBytes.size < 37) return false
+
+    val flag = authenticatorDataBytes[32].toInt()
+
+    // Verify that the UP bit of the flags in authData is set.
+    if ((flag and 0x01) != 0x01) return false
+
+    // If user verification was determined to be required, verify that
+    // the UV bit of the flags in authData is set. Otherwise, ignore the
+    // value of the UV flag.
+    if (webAuthn.userVerificationRequired && (flag and 0x04) != 0x04) return false
+
+    // If the BE bit of the flags in authData is not set, verify that
+    // the BS bit is not set.
+    if ((flag and 0x08) != 0x08 && (flag and 0x10) == 0x10) return false
+
+    // Check that response is for an authentication assertion
+    val expectedType = "\"type\":\"webauthn.get\""
+    val typeSlice = webAuthn.clientDataJSON.substring(
+        webAuthn.typeIndex,
+        webAuthn.typeIndex + expectedType.length
+    )
+    if (typeSlice != expectedType) return false
+
+    // Check that hash is in the clientDataJSON.
+    val challenge =
+        extractChallenge(webAuthn.clientDataJSON, webAuthn.challengeIndex) ?: return false
+    // Validate the challenge in the clientDataJSON.
+    return bytesToHex(base64UrlToBytes(challenge)) == hash
+}
+
+@ExcludeFromGeneratedCCReport
+internal fun verifyRaw(
+    publicKey: PublicKey,
+    signature: String,
+    clientDataJSON: String,
+    authenticatorData: String
+): Boolean {
+    val signatureBytes = base64UrlToBytes(signature)
+    val sig = Signature.getInstance("SHA256withECDSA")
+    sig.initVerify(publicKey)
+    val md = MessageDigest.getInstance("SHA-256")
+    val clientDataHash = md.digest(base64UrlToBytes(clientDataJSON))
+    val signatureBase = base64UrlToBytes(authenticatorData) + clientDataHash
+    sig.update(signatureBase)
+    return sig.verify(signatureBytes)
+}
+
+@ExcludeFromGeneratedCCReport
+internal fun verify(
+    hash: String,
+    publicKey: String,
+    hexSignature: String,
+    webauthn: WebAuthnData
+): Boolean {
+    val ecPublicKey = parsePublicKey(publicKey)
+    val signature = parseSignature(hexSignature)
+    val clientDataJSON =
+        bytesToBase64Url(webauthn.clientDataJSON.toByteArray()).replace("\n", "")
+    val authenticatorDataBytes = hexStringToByteArray(webauthn.authenticatorData)
+    val authenticatorData =
+        bytesToBase64Url(authenticatorDataBytes).replace("\n", "")
+    if (!verifyBasic(hash, authenticatorDataBytes, webauthn)) {
+        return false
+    }
+    return verifyRaw(ecPublicKey, signature, clientDataJSON, authenticatorData)
+}
+
+@ExcludeFromGeneratedCCReport
+private fun extractChallenge(clientDataJSON: String, challengeIndex: Int): String? {
+    val regex = """"challenge":"([^"]+)"""".toRegex()
+    val challengeSubstring = clientDataJSON.substring(challengeIndex)
+    val matchResult = regex.find(challengeSubstring)
+    return matchResult?.groups?.get(1)?.value
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/smartAccount/GetMinimumVerificationGasLimitUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/smartAccount/GetMinimumVerificationGasLimitUtils.kt
new file mode 100644
index 0000000..032527a
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/smartAccount/GetMinimumVerificationGasLimitUtils.kt
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.utils.smartAccount
+
+import com.circle.modularwallets.core.chains.Mainnet
+import com.circle.modularwallets.core.chains.Sepolia
+import com.circle.modularwallets.core.constants.MAINNET_MINIMUM_UNDEPLOY_VERIFICATION_GAS_LIMIT
+import com.circle.modularwallets.core.constants.MAINNET_MINIMUM_VERIFICATION_GAS_LIMIT
+import com.circle.modularwallets.core.constants.MINIMUM_UNDEPLOY_VERIFICATION_GAS_LIMIT
+import com.circle.modularwallets.core.constants.MINIMUM_VERIFICATION_GAS_LIMIT
+import com.circle.modularwallets.core.constants.SEPOLIA_MINIMUM_UNDEPLOY_VERIFICATION_GAS_LIMIT
+import com.circle.modularwallets.core.constants.SEPOLIA_MINIMUM_VERIFICATION_GAS_LIMIT
+import com.circle.modularwallets.core.constants.gweiUnits
+import java.math.BigInteger
+
+/**
+ * Gets the minimum verification gas limit for a given chain.
+ *
+ * @param deployed Whether the smart account is deployed.
+ * @param chainId The chain ID.
+ * @return The chain-specific minimum verification gas limit or the default value if the chain is not supported.
+ */
+@Throws(Exception::class)
+fun getMinimumVerificationGasLimit(deployed: Boolean, chainId: Long): BigInteger {
+    when(chainId){
+        Sepolia.chainId -> {
+            return if(deployed){
+                SEPOLIA_MINIMUM_VERIFICATION_GAS_LIMIT
+            } else{
+                SEPOLIA_MINIMUM_UNDEPLOY_VERIFICATION_GAS_LIMIT
+            }
+        }
+        Mainnet.chainId -> {
+            return if(deployed){
+                MAINNET_MINIMUM_VERIFICATION_GAS_LIMIT
+            } else{
+                MAINNET_MINIMUM_UNDEPLOY_VERIFICATION_GAS_LIMIT
+            }
+        }
+        else -> {
+            return if(deployed){
+                MINIMUM_VERIFICATION_GAS_LIMIT
+            } else{
+                MINIMUM_UNDEPLOY_VERIFICATION_GAS_LIMIT
+            }
+        }
+    }
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/unit/FormatUnitUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/unit/FormatUnitUtils.kt
new file mode 100644
index 0000000..8db9189
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/unit/FormatUnitUtils.kt
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.utils.unit
+
+import com.circle.modularwallets.core.constants.gweiUnits
+import java.math.BigInteger
+
+/**
+ * Converts a numerical value in wei to a string representation in gwei.
+ *
+ * @param wei The numerical value in wei.
+ * @param unit The unit of the value (default is "wei").
+ * @return The string representation of the value in gwei.
+ */
+@Throws(Exception::class)
+@JvmOverloads
+fun formatGwei(wei: BigInteger?, unit: String = "wei"): String? {
+    wei ?: return null
+    val decimals = gweiUnits[unit] ?: 0
+    return formatUnits(wei, decimals)
+}
+
+/**
+ * Converts a numerical value in wei to a string representation in a specified unit.
+ *
+ * @param value The numerical value in wei.
+ * @param decimals The number of decimal places to consider for the unit.
+ * @return The string representation of the value in the specified unit.
+ */
+@Throws(Exception::class)
+fun formatUnits(value: BigInteger, decimals: Int): String {
+
+    var display = value.toString()
+
+
+    val negative = display.startsWith('-')
+    if (negative) display = display.substring(1)
+
+
+    display = display.padStart(decimals, '0')
+
+
+    val integerPart = display.substring(0, display.length - decimals)
+    var fractionPart = display.substring(display.length - decimals)
+
+
+    fractionPart = fractionPart.replace(Regex("0+$"), "")
+
+
+    return "${if (negative) "-" else ""}${if (integerPart.isEmpty()) "0" else integerPart}" +
+            if (fractionPart.isNotEmpty()) ".$fractionPart" else ""
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/unit/ParseUnitUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/unit/ParseUnitUtils.kt
new file mode 100644
index 0000000..a898b0f
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/unit/ParseUnitUtils.kt
@@ -0,0 +1,116 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.utils.unit
+
+import com.circle.modularwallets.core.constants.etherUnits
+import com.circle.modularwallets.core.constants.gweiUnits
+import com.circle.modularwallets.core.errors.BaseError
+import java.math.BigInteger
+import kotlin.math.round
+
+/**
+ * Converts a string representation of gwei to numerical wei.
+ *
+ * @param value The string representation of gwei.
+ * @param unit The unit of the value (default is "wei").
+ * @return The numerical value in wei.
+ * @throws IllegalArgumentException If the unit is invalid.
+ * @throws BaseError If the value is not a valid decimal number.
+ */
+@JvmOverloads
+fun parseGwei(value: String, unit: String = "wei"): BigInteger {
+    val decimals = gweiUnits[unit] ?: throw BaseError("Invalid unit: $unit")
+    return parseUnits(value, decimals)
+}
+
+/**
+ * Converts a string representation of ether to numerical wei.
+ *
+ * @param value The string representation of ether.
+ * @param unit The unit of the value (default is "wei").
+ * @return The numerical value in wei.
+ */
+@JvmOverloads
+@Throws(Exception::class)
+fun parseEther(value: String, unit: String = "wei"): BigInteger {
+    val decimals = etherUnits[unit] ?: throw BaseError("Invalid unit: $unit")
+    return parseUnits(value, decimals)
+}
+
+/**
+ * Multiplies a string representation of a number by a given exponent of base 10 (10^exponent).
+ *
+ * @param value The string representation of the number.
+ * @param decimals The exponent of base 10.
+ * @return The numerical value as a BigInteger.
+ * @throws IllegalArgumentException If the decimals value is invalid.
+ */
+@Throws(Exception::class)
+fun parseUnits(value: String, decimals: Int): BigInteger {
+    // Validate the input string against the regex
+    if (!Regex("""^(-?)([0-9]*)\.?([0-9]*)$""").matches(value)) {
+        throw BaseError("InvalidDecimalNumberError $value")
+    }
+
+    // Split the input into integer and fraction parts
+    var (integerPart, fractionPart) = value.split('.').let {
+        it[0] to (it.getOrNull(1) ?: "0")
+    }
+
+    val negative = integerPart.startsWith('-')
+    if (negative) integerPart = integerPart.substring(1)
+
+    // Trim trailing zeros
+    var fraction = fractionPart.replace(Regex("(0+)$"), "")
+
+    // Handle case when decimals is zero
+    if (decimals == 0) {
+        if (round("0.$fraction".toDouble()) == 1.0) {
+            val updatedInteger = BigInteger(integerPart) + BigInteger.ONE
+            return BigInteger("${if (negative) "-" else ""}${updatedInteger}")
+        }
+        fraction = ""
+    } else if (fraction.length > decimals) {
+        val left = fraction.substring(0, decimals - 1)
+        val unit = fraction.substring(decimals - 1, decimals)
+        val right = fraction.substring(decimals)
+
+        val rounded = round("$unit.$right".toDouble()).toInt()
+
+        if (rounded > 9) {
+            fraction =
+                BigInteger(left).add(BigInteger.ONE).toString() + "0".padStart(left.length + 1, '0')
+        } else {
+            fraction = "$left$rounded"
+        }
+
+        if (fraction.length > decimals) {
+            fraction = fraction.substring(1)
+            val updatedInteger = BigInteger(integerPart) + BigInteger.ONE
+            integerPart = updatedInteger.toString()
+        }
+
+        fraction = fraction.substring(0, decimals)
+    } else {
+        fraction = fraction.padEnd(decimals, '0')
+    }
+
+    return BigInteger("${if (negative) "-" else ""}$integerPart$fraction")
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/userOperation/GetUserOperationHashUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/userOperation/GetUserOperationHashUtils.kt
new file mode 100644
index 0000000..15cc4d8
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/userOperation/GetUserOperationHashUtils.kt
@@ -0,0 +1,109 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.utils.userOperation
+
+import com.circle.modularwallets.core.models.EntryPoint
+import com.circle.modularwallets.core.models.UserOperationV07
+import com.circle.modularwallets.core.utils.data.concat
+import com.circle.modularwallets.core.utils.data.pad
+import com.circle.modularwallets.core.utils.encoding.bigIntegerToHex
+import org.web3j.abi.DefaultFunctionEncoder
+import org.web3j.abi.datatypes.Address
+import org.web3j.abi.datatypes.Type
+import org.web3j.abi.datatypes.generated.Bytes32
+import org.web3j.abi.datatypes.generated.Uint256
+import org.web3j.crypto.Hash
+import org.web3j.utils.Numeric
+import java.math.BigInteger
+
+/**
+ * Generates the hash of a user operation.
+ *
+ * @param chainId The ID of the blockchain network.
+ * @param entryPointAddress The address of the entry point contract. Default is the address of EntryPoint.V07.
+ * @param userOp The user operation to hash.
+ * @return The hash of the user operation as a hex string.
+ */
+
+@JvmOverloads
+fun getUserOperationHash(
+    chainId: Long,
+    entryPointAddress: String = EntryPoint.V07.address,
+    userOp: UserOperationV07
+): String {
+    val accountGasLimits = Numeric.hexStringToByteArray(
+        concat(
+            pad(bigIntegerToHex(userOp.verificationGasLimit), 16),
+            pad(bigIntegerToHex(userOp.callGasLimit), 16)
+        )
+    )
+    val callDataHashed = Hash.sha3(Numeric.hexStringToByteArray(userOp.callData))
+    val gasFees = Numeric.hexStringToByteArray(
+        concat(
+            pad(bigIntegerToHex(userOp.maxPriorityFeePerGas), 16),
+            pad(bigIntegerToHex(userOp.maxFeePerGas), 16)
+        )
+    )
+    val initCodeHashed = Hash.sha3(
+        Numeric.hexStringToByteArray(
+            if (userOp.factory != null && userOp.factoryData != null) concat(
+                userOp.factory!!,
+                userOp.factoryData!!
+            ) else "0x"
+        )
+    )
+    val paymasterAndDataHashed = Hash.sha3(Numeric.hexStringToByteArray(userOp.paymaster?.let {
+        concat(
+            it,
+            pad(bigIntegerToHex(userOp.paymasterVerificationGasLimit ?: BigInteger.ZERO), 16),
+            pad(bigIntegerToHex(userOp.paymasterPostOpGasLimit ?: BigInteger.ZERO), 16),
+            userOp.paymasterData ?: "0x"
+        )
+    } ?: "0x"))
+    val encoder = DefaultFunctionEncoder()
+    val packedUserOp = encoder.encodeParameters(
+        listOf<Type<*>>(
+            Address(userOp.sender),
+            Uint256(userOp.nonce),
+            Bytes32(initCodeHashed),
+            Bytes32(callDataHashed),
+            Bytes32(accountGasLimits),
+            Uint256(userOp.preVerificationGas),
+            Bytes32(gasFees),
+            Bytes32(paymasterAndDataHashed),
+        )
+    )
+    return Hash.sha3(
+        encoder.encodeParameters(
+            listOf<Type<*>>(
+                Bytes32(Hash.sha3(Numeric.hexStringToByteArray(packedUserOp))),
+                Address(entryPointAddress),
+                Uint256(chainId)
+            )
+        )
+    )
+}
+
+
+internal fun parseFactoryAddressAndData(initCode: String): Pair<String, String> {
+    val factoryAddress = initCode.substring(0, 42)
+    val factoryData = ("0x${initCode.substring(42)}")
+    return Pair(factoryAddress, factoryData)
+}
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/webauthn/CredentialManagerUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/webauthn/CredentialManagerUtils.kt
new file mode 100644
index 0000000..6b5067c
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/webauthn/CredentialManagerUtils.kt
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.utils.webauthn
+
+import android.content.Context
+import androidx.credentials.CreatePublicKeyCredentialRequest
+import androidx.credentials.CreatePublicKeyCredentialResponse
+import androidx.credentials.CredentialManager
+import androidx.credentials.GetCredentialRequest
+import androidx.credentials.GetPasswordOption
+import androidx.credentials.GetPublicKeyCredentialOption
+import androidx.credentials.PublicKeyCredential
+import androidx.credentials.exceptions.CreateCredentialException
+import com.circle.modularwallets.core.annotation.ExcludeFromGeneratedCCReport
+import com.circle.modularwallets.core.errors.BaseError
+import com.circle.modularwallets.core.errors.BaseErrorParameters
+
+@ExcludeFromGeneratedCCReport
+internal suspend fun createPasskey(
+    context: Context,
+    registrationJson: String
+): CreatePublicKeyCredentialResponse {
+    try {
+        val request = CreatePublicKeyCredentialRequest(registrationJson)
+        val credentialManager = CredentialManager.create(context)
+        val response: CreatePublicKeyCredentialResponse = credentialManager.createCredential(
+            context,
+            request
+        ) as CreatePublicKeyCredentialResponse
+
+        PublicKeyCredential(response.registrationResponseJson)
+        return response
+    } catch (e: CreateCredentialException) {
+        e.message?.let{
+            if(it.contains("User cancelled the selector")) {
+                throw BaseError(it, BaseErrorParameters(e))
+            }
+        }
+        throw BaseError("credential request failed.", BaseErrorParameters(e, registrationJson))
+    }
+}
+
+@ExcludeFromGeneratedCCReport
+internal suspend fun getSavedCredentials(context: Context, authJson: String): String {
+    val getPublicKeyCredentialOption =
+        GetPublicKeyCredentialOption(authJson, null)
+    val credentialManager = CredentialManager.create(context)
+    val result = try {
+        credentialManager.getCredential(
+            context,
+            GetCredentialRequest(
+                listOf(
+                    getPublicKeyCredentialOption,
+                    GetPasswordOption()
+                )
+            )
+        )
+    } catch (e: Exception) {
+        e.message?.let{
+            if(it.contains("User cancelled the selector")) {
+                throw BaseError(it, BaseErrorParameters(e))
+            }
+        }
+        throw BaseError("credential request failed.", BaseErrorParameters(e))
+    }
+
+    if (result.credential is PublicKeyCredential) {
+        val cred = result.credential as PublicKeyCredential
+        return cred.authenticationResponseJson
+    }
+    throw BaseError("credential request failed. No PublicKeyCredential")
+}
\ No newline at end of file
diff --git a/lib/src/main/java/com/circle/modularwallets/core/utils/webauthn/OptionsUtils.kt b/lib/src/main/java/com/circle/modularwallets/core/utils/webauthn/OptionsUtils.kt
new file mode 100644
index 0000000..11263a9
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/utils/webauthn/OptionsUtils.kt
@@ -0,0 +1,61 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.circle.modularwallets.core.utils.webauthn
+
+import android.util.Base64
+import com.circle.modularwallets.core.apis.rp.PublicKeyCredentialDescriptor
+import com.circle.modularwallets.core.apis.rp.PublicKeyCredentialRequestOptions
+import com.circle.modularwallets.core.utils.signature.bytesToBase64Url
+import com.circle.modularwallets.core.utils.toJson
+import org.web3j.utils.Numeric.hexStringToByteArray
+import java.security.SecureRandom
+
+internal fun getRequestOptions(
+    rpId: String,
+    allowCredentialId: String? = null,
+    hex: String
+): Pair<PublicKeyCredentialRequestOptions, String> {
+    val challenge: String = bytesToBase64Url(hexStringToByteArray(hex)) //getEncodedChallenge()
+    val allowCredentials = if (allowCredentialId?.isNotBlank() == true) mutableListOf(
+        PublicKeyCredentialDescriptor(allowCredentialId)
+    ) else null
+    val options = PublicKeyCredentialRequestOptions(challenge, rpId, allowCredentials)
+    return Pair(options, toJson(options))
+}
+
+private fun getEncodedUserId(): String {
+    val random = SecureRandom()
+    val bytes = ByteArray(64)
+    random.nextBytes(bytes)
+    return Base64.encodeToString(
+        bytes,
+        Base64.NO_WRAP or Base64.URL_SAFE or Base64.NO_PADDING
+    )
+}
+
+internal fun getEncodedChallenge(): String {
+    val random = SecureRandom()
+    val bytes = ByteArray(32)
+    random.nextBytes(bytes)
+    return Base64.encodeToString(
+        bytes,
+        Base64.NO_WRAP or Base64.URL_SAFE or Base64.NO_PADDING
+    )
+}
diff --git a/settings.gradle.kts b/settings.gradle.kts
new file mode 100644
index 0000000..f0c6c07
--- /dev/null
+++ b/settings.gradle.kts
@@ -0,0 +1,23 @@
+pluginManagement {
+    repositories {
+        google {
+            content {
+                includeGroupByRegex("com\\.android.*")
+                includeGroupByRegex("com\\.google.*")
+                includeGroupByRegex("androidx.*")
+            }
+        }
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+rootProject.name = "CircleModularWalletsCore"
+include(":lib")