diff --git a/Sources/Web3Core/EthereumNetwork/Request/APIRequest+ComputedProperties.swift b/Sources/Web3Core/EthereumNetwork/Request/APIRequest+ComputedProperties.swift
index fc711ce4b..892f7fa69 100644
--- a/Sources/Web3Core/EthereumNetwork/Request/APIRequest+ComputedProperties.swift
+++ b/Sources/Web3Core/EthereumNetwork/Request/APIRequest+ComputedProperties.swift
@@ -22,7 +22,7 @@ extension APIRequest {
             return [RequestParameter]()
 
         case .estimateGas(let transactionParameters, let blockNumber):
-            return [.transaction(transactionParameters), .string(blockNumber.description)]
+            return [.transaction(transactionParameters), blockNumber.map { .string($0.description) }].compactMap { $0 }
 
         case let .sendRawTransaction(hash):
             return [.string(hash)]
diff --git a/Sources/Web3Core/EthereumNetwork/Request/APIRequest.swift b/Sources/Web3Core/EthereumNetwork/Request/APIRequest.swift
index cb057da7e..900985171 100644
--- a/Sources/Web3Core/EthereumNetwork/Request/APIRequest.swift
+++ b/Sources/Web3Core/EthereumNetwork/Request/APIRequest.swift
@@ -96,7 +96,7 @@ public enum APIRequest {
     /// - Parameters:
     ///     - TransactionParameters: parameters of planned transaction
     ///     - BlockNumber: block where it should be evaluated
-    case estimateGas(CodableTransaction, BlockNumber)
+    case estimateGas(CodableTransaction, BlockNumber?)
 
     /// Send raw transaction
     /// - Parameters:
diff --git a/Sources/Web3Core/Transaction/CodableTransaction.swift b/Sources/Web3Core/Transaction/CodableTransaction.swift
index 1246e2714..ebf706940 100644
--- a/Sources/Web3Core/Transaction/CodableTransaction.swift
+++ b/Sources/Web3Core/Transaction/CodableTransaction.swift
@@ -240,7 +240,7 @@ extension CodableTransaction: Codable {
             try containier.encode(gasLimit.hexString, forKey: .gasLimit)
         }
 
-        if let gasPrice = gasPrice, !gasPrice.isZero {
+        if let gasPrice = gasPrice/*, !gasPrice.isZero*/ {
             try containier.encode(gasPrice.hexString, forKey: .gasPrice)
         }
 
@@ -292,10 +292,10 @@ extension CodableTransaction {
     ///   - s: signature s parameter (default 0) - will get set properly once signed
     ///   - parameters: EthereumParameters object containing additional parameters for the transaction like gas
     public init(type: TransactionType? = nil, to: EthereumAddress, nonce: BigUInt = 0,
-                chainID: BigUInt = 0, value: BigUInt = 0, data: Data = Data(),
+                chainID: BigUInt = 0, value: BigUInt = 0, data: Data = Data(), callOnBlock: BlockNumber? = .latest,
                 gasLimit: BigUInt = 0, maxFeePerGas: BigUInt? = nil, maxPriorityFeePerGas: BigUInt? = nil, gasPrice: BigUInt? = nil,
                 accessList: [AccessListEntry]? = nil, v: BigUInt = 1, r: BigUInt = 0, s: BigUInt = 0) {
-        callOnBlock = .latest
+        self.callOnBlock = callOnBlock
 
         envelope = EnvelopeFactory.createEnvelope(type: type, to: to, nonce: nonce, chainID: chainID, value: value, data: data, gasLimit: gasLimit, maxFeePerGas: maxFeePerGas, maxPriorityFeePerGas: maxPriorityFeePerGas, gasPrice: gasPrice, accessList: accessList, v: v, r: r, s: s)
     }
diff --git a/Sources/web3swift/EthereumAPICalls/Ethereum/IEth+Defaults.swift b/Sources/web3swift/EthereumAPICalls/Ethereum/IEth+Defaults.swift
index 8d695cba2..e70e14f69 100644
--- a/Sources/web3swift/EthereumAPICalls/Ethereum/IEth+Defaults.swift
+++ b/Sources/web3swift/EthereumAPICalls/Ethereum/IEth+Defaults.swift
@@ -20,7 +20,7 @@ public extension IEth {
         try await estimateGas(for: transaction, onBlock: .latest)
     }
 
-    func estimateGas(for transaction: CodableTransaction, onBlock: BlockNumber) async throws -> BigUInt {
+    func estimateGas(for transaction: CodableTransaction, onBlock: BlockNumber?) async throws -> BigUInt {
         let request = APIRequest.estimateGas(transaction, onBlock)
         return try await APIRequest.sendRequest(with: provider, for: request).result
     }
diff --git a/Sources/web3swift/EthereumAPICalls/Ethereum/IEth.swift b/Sources/web3swift/EthereumAPICalls/Ethereum/IEth.swift
index 0ce33372f..fb4468eae 100755
--- a/Sources/web3swift/EthereumAPICalls/Ethereum/IEth.swift
+++ b/Sources/web3swift/EthereumAPICalls/Ethereum/IEth.swift
@@ -13,7 +13,7 @@ public protocol IEth {
     func send(_ transaction: CodableTransaction) async throws -> TransactionSendingResult
     func send(raw data: Data) async throws -> TransactionSendingResult
 
-    func estimateGas(for transaction: CodableTransaction, onBlock: BlockNumber) async throws -> BigUInt
+    func estimateGas(for transaction: CodableTransaction, onBlock: BlockNumber?) async throws -> BigUInt
     func feeHistory(blockCount: BigUInt, block: BlockNumber, percentiles: [Double]) async throws -> Oracle.FeeHistory
     func ownedAccounts() async throws -> [EthereumAddress]
     func getBalance(for address: EthereumAddress, onBlock: BlockNumber) async throws -> BigUInt
diff --git a/Sources/web3swift/Web3/Web3+Resolver.swift b/Sources/web3swift/Web3/Web3+Resolver.swift
index 1fa3d6299..2f2fafbdd 100644
--- a/Sources/web3swift/Web3/Web3+Resolver.swift
+++ b/Sources/web3swift/Web3/Web3+Resolver.swift
@@ -88,7 +88,7 @@ public class PolicyResolver {
 
 extension PolicyResolver {
     private func estimateGas(for transaction: CodableTransaction) async throws -> BigUInt {
-        let request: APIRequest = .estimateGas(transaction, transaction.callOnBlock ?? .latest)
+        let request: APIRequest = .estimateGas(transaction, transaction.callOnBlock)
         let response: APIResponse<BigUInt> = try await APIRequest.sendRequest(with: provider, for: request)
         return response.result
     }