diff --git a/docs/apps.rst b/docs/apps.rst
index f3f6332..a73008f 100644
--- a/docs/apps.rst
+++ b/docs/apps.rst
@@ -10,6 +10,11 @@ List of Functions
 * :func:`apps.getLaunchCommandLineParam`
 
 
+List of Callbacks
+-----------------
+
+* :func:`apps.onNewUrlLaunchParameters`
+
 Function Reference
 ------------------
 
@@ -43,16 +48,19 @@ Function Reference
         -- Unlock game content
     end
 
-.. function:: apps.getLaunchCommandLineParam()
+.. function:: apps.getLaunchCommandLine()
 
     :returns: (`string`) The launch command line parameters
     :SteamWorks: `GetLaunchCommandLine <https://partner.steamgames.com/doc/api/ISteamApps#GetLaunchCommandLine>`_
 
     Gets the launch command line parameters. Use it to for example parse it for a connect string when implementing game invite functionality using :func:`friends.inviteUserToGame`.
 
+    If Steam is installed, you can request launching a Steam game by navigating to a `steam://run/<appid>//<params>` URL.
+
+
 **Example**::
 
-    local params = Steam.apps.getLaunchCommandLineParam()
+    local params = Steam.apps.getLaunchCommandLine()
     local connect_string = tryParseConnectString(params)
     if connect_string then
         initiateJoinGame(connect_string)
@@ -60,4 +68,18 @@ Function Reference
 
 .. warning::
 
-    This is currently hardcoded in luasteam to a 1024 characters maximum.
\ No newline at end of file
+    This is currently hardcoded in luasteam to a 1024 characters maximum.
+
+
+
+Callbacks Reference
+-------------------
+
+.. function:: apps.onNewUrlLaunchParameters()
+
+    :returns: nothing
+    :SteamWorks: `NewUrlLaunchParameters_t <https://partner.steamgames.com/doc/api/ISteamApps#NewUrlLaunchParameters_t>`_
+
+    Called by Steam when a `steam://run/<appid>//<params>` URL is navigated to when the game is already running. This callback has no data, use :func:`apps.getLaunchCommandLine` to get the launch parameters from the most recently used URL.
+
+    The callback that gets called when you join another player's game inside Steam while the game is running is :func:`friends.onGameRichPresenceJoinRequested`.
diff --git a/src/apps.cpp b/src/apps.cpp
index 4798042..f544896 100644
--- a/src/apps.cpp
+++ b/src/apps.cpp
@@ -4,6 +4,33 @@
 // ======== SteamApps =========
 // ============================
 
+class CallbackListener;
+CallbackListener *apps_listener = nullptr;
+int apps_ref = LUA_NOREF;
+
+class CallbackListener {
+  private:
+    STEAM_CALLBACK(CallbackListener, OnNewUrlLaunchParameters, NewUrlLaunchParameters_t);
+};
+
+void CallbackListener::OnNewUrlLaunchParameters(NewUrlLaunchParameters_t *data) {
+    if (data == nullptr) {
+        return;
+    }
+    lua_State *L = luasteam::global_lua_state;
+    if (!lua_checkstack(L, 4)) {
+        return;
+    }
+    lua_rawgeti(L, LUA_REGISTRYINDEX, apps_ref);
+    lua_getfield(L, -1, "onNewUrlLaunchParameters");
+    if (lua_isnil(L, -1)) {
+        lua_pop(L, 2);
+    } else {
+        lua_call(L, 0, 0);
+        lua_pop(L, 1);
+    }
+}
+
 // const char * GetCurrentGameLanguage();
 EXTERN int luasteam_getCurrentGameLanguage(lua_State *L) {
     lua_pushstring(L, SteamApps()->GetCurrentGameLanguage());
@@ -32,11 +59,20 @@ void add_apps(lua_State *L) {
     add_func(L, "getCurrentGameLanguage", luasteam_getCurrentGameLanguage);
     add_func(L, "isDlcInstalled", luasteam_isDlcInstalled);
     add_func(L, "getLaunchCommandLine", luasteam_getLaunchCommandLine);
+    lua_pushvalue(L, -1);
+    apps_ref = luaL_ref(L, LUA_REGISTRYINDEX);
     lua_setfield(L, -2, "apps");
 }
 
-void init_apps(lua_State *L) {}
+void init_apps(lua_State *L) {
+    apps_listener = new CallbackListener(); 
+}
 
-void shutdown_apps(lua_State *L) {}
+void shutdown_apps(lua_State *L) {
+    luaL_unref(L, LUA_REGISTRYINDEX, apps_ref);
+    apps_ref = LUA_NOREF;
+    delete apps_listener;
+    apps_listener = nullptr;
+}
 
 } // namespace luasteam