diff --git a/pkg/chain/chain_constants.go b/pkg/chain/chain_constants.go
index a364f0b..d3f73f8 100644
--- a/pkg/chain/chain_constants.go
+++ b/pkg/chain/chain_constants.go
@@ -25,18 +25,18 @@ type NetworkType struct {
 }
 
 type L2ChainIDs struct {
-	OPTIMISM                       int
-	OPTIMISM_GOERLI                int
-	OPTIMISM_HARDHAT_LOCAL         int
-	OPTIMISM_HARDHAT_DEVNET        int
-	OPTIMISM_BEDROCK_LOCAL_DEVNET  int
-	OPTIMISM_BEDROCK_ALPHA_TESTNET int
-	BASE_GOERLI                    int
-	ZORA_GOERLI                    int
-	ZORA_MAINNET                   int
-	OPTIMISM_SEPOLIA               int
-	BASE_SEPOLIA                   int
-	BASE_MAINNET                   int
+	OPTIMISM                       uint64
+	OPTIMISM_GOERLI                uint64
+	OPTIMISM_HARDHAT_LOCAL         uint64
+	OPTIMISM_HARDHAT_DEVNET        uint64
+	OPTIMISM_BEDROCK_LOCAL_DEVNET  uint64
+	OPTIMISM_BEDROCK_ALPHA_TESTNET uint64
+	BASE_GOERLI                    uint64
+	ZORA_GOERLI                    uint64
+	ZORA_MAINNET                   uint64
+	OPTIMISM_SEPOLIA               uint64
+	BASE_SEPOLIA                   uint64
+	BASE_MAINNET                   uint64
 }
 
 var L2_CHAIN_ID = L2ChainIDs{
@@ -78,10 +78,10 @@ var OPTIMISM_PORTAL_ADDRESS = NetworkType{
 }
 
 type L1Contracts struct {
-	L1CrossDomainMessenger string
-	StateCommitmentChain   string
-	OptimismPortal         string
-	L2OutputOracle         string
+	L1CrossDomainMessenger string `json:"l1CrossDomainMessenger"`
+	StateCommitmentChain   string `json:"StateCommitmentChain"`
+	OptimismPortal         string `json:"OptimismPortal"`
+	L2OutputOracle         string `json:"l2OutputOracle"`
 }
 
 type ContractAddresses struct {
@@ -120,8 +120,8 @@ func getL1ContractsByNetworkName(network string) L1Contracts {
 	return L1Contracts
 }
 
-func getContractAddresses() map[int]map[string]L1Contracts {
-	CONTRACT_ADDRESSES := map[int]map[string]L1Contracts{
+func getContractAddresses() map[uint64]map[string]L1Contracts {
+	CONTRACT_ADDRESSES := map[uint64]map[string]L1Contracts{
 		L2_CHAIN_ID.OPTIMISM: {
 			"l1": getL1ContractsByNetworkName("mainnet"),
 			// "l2": DEFAULT_L2_CONTRACT_ADDRESS,
diff --git a/pkg/chain/contracts.go b/pkg/chain/contracts.go
index 3175c0b..3012fec 100644
--- a/pkg/chain/contracts.go
+++ b/pkg/chain/contracts.go
@@ -11,15 +11,15 @@ import (
 	"github.com/ethereum-optimism/optimism/op-bindings/bindings"
 )
 
-func GetOracleAddressbyChainID(l2ChainID int) string {
+func GetL1OracleContractAddressByChainID(chainID uint64) string {
 	ContractAddresses := getContractAddresses()
-	address := ContractAddresses[l2ChainID]["l1"].L2OutputOracle
+	address := ContractAddresses[chainID]["l1"].L2OutputOracle
 	return address
 }
 
 // TODO: Create oracle Struct with required functions
-func OracleContractInstance(client *ethclient.Client, l2ChainID int, log log.Logger) (*bindings.L2OutputOracle, error) {
-	oracleContractAddress := GetOracleAddressbyChainID(l2ChainID)
+func OracleContractInstance(client *ethclient.Client, chainID uint64, log log.Logger) (*bindings.L2OutputOracle, error) {
+	oracleContractAddress := GetL1OracleContractAddressByChainID(chainID)
 
 	contract, err := bindings.NewL2OutputOracle(common.HexToAddress(oracleContractAddress), client)
 
@@ -31,14 +31,14 @@ func OracleContractInstance(client *ethclient.Client, l2ChainID int, log log.Log
 }
 
 // TODO: Use EthClientInterface
-func CreateContractInstance(url string, l2ChainID int, logger log.Logger) *bindings.L2OutputOracle {
+func CreateContractInstance(url string, chainID uint64, logger log.Logger) *bindings.L2OutputOracle {
 	client, err := ethclient.Dial(url)
 
 	if err != nil {
 		logger.Errorf("Error occurred while connecting %w", err)
 	}
 
-	contract, err := OracleContractInstance(client, l2ChainID, logger)
+	contract, err := OracleContractInstance(client, chainID, logger)
 
 	if err != nil {
 		logger.Errorf("Error occurred while creating contract instance %w", err)