Sign Starknet transactions

You can sign Starknet transactions using the get-starknet library or the wallet_invokeSnap JSON-RPC method.

Prerequisites

Connect to Starknet from your dapp.

Sign a transaction

Sign a Starknet transaction using the following:

get-starknet

const signStarknetTransaction = async (wallet, contractAddress, entrypoint, calldata) => {
  try {
    if(wallet?.isConnected !== true){
      throw("Wallet not connected");
    } 
  
    // Sign the transaction.
    const result = await wallet?.account?.signer.signTransaction({
      contractAddress: contractAddress,  // The address of the contract.
      entrypoint: entrypoint,            // The function to call in the contract.
      calldata: calldata                 // The parameters to pass to the function.
    });
    console.log("Transaction signed successfully:", result);
    return result;
  } catch (error) {
    console.error("Error signing transaction:", error);
  }
};

wallet_invokeSnap

const signStarknetTransactionWithSnap = async (contractAddress, entrypoint, calldata, chainId, address) => {
  try {
    const provider = await getEip6963Provider();
    
    if (!provider) {
      throw new Error("MetaMask not detected or Snaps not supported");
    }
    // Connect to the Starknet Snap if it's not already connected.
    await provider.request({
      method: "wallet_requestSnaps",
      params: {
        "npm:@consensys/starknet-snap": {}
      }
    });
    console.log("Starknet Snap connected");

    // Use the wallet_invokeSnap method to sign the transaction.
    const response = await provider.request({
      method: "wallet_invokeSnap",
      params: {
        snapId: "npm:@consensys/starknet-snap",
        request: {
          method: "starkNet_signTransaction",
          params: {
            address,              // The address of the account.
            chainId,              // The chain ID of the request.
            transactions: {
                contractAddress,  // The address of the contract.
                entrypoint,       // The function to call in the contract.
                calldata          // The parameters to pass to the function (as an array).
            }
          }
        }
      }
    });
    
    console.log("Transaction signed successfully:", response);
    return response;
  } catch (error) {
    console.error("Error signing transaction:", error);
    throw error;
  }
};

// Example usage:
const contractAddress = "0x5B38Da6a701c568545dCfcB03FcB875f56beddC4";
const entrypoint = "transfer";
const calldata = ["0xRecipientAddress", "1000"];

signStarknetTransactionWithSnap(contractAddress, entrypoint, calldata)
  .then(result => console.log("Signed transaction result:", result))
  .catch(error => console.error("Transaction error:", error));