Sign Transactions on EVM chains

Step 1. Create EVM wallets

When creating a developer-controlled wallet, pass EVM-TESTNET or EVM in the blockchains field. This wallet can be used to sign transactions on any EVM chain.

The following example code shows how to create a wallet using the Circle Developer SDK.

const response = await circleDeveloperSdk.createWallets({
  accountType: 'EOA',
  blockchains: ['EVM-TESTNET'],
  count: 2,
  walletSetId: '<wallet-set-id>'
});

Step 2. Build transactions

You can sign a transaction object using the API or SDK.

The following example code shows how to build a transaction object.

const Web3 = require('web3');
const EthereumTx = require('ethereumjs-tx').Transaction;

// Connect to an Ethereum node
const web3 = new Web3('https://mainnet.infura.io/v3/YOUR-PROJECT-ID');

async function buildUnsignedRawTransaction() {
    // Sender's address
    const senderAddress = '0x1234...'; // Replace with the sender's address

    // Recipient's address
    const recipientAddress = '0x5678...'; // Replace with the recipient's address

    // Amount to send in wei
    const amountToSend = web3.utils.toWei('0.1', 'ether');

    // Get the nonce
    const nonce = await web3.eth.getTransactionCount(senderAddress);

    // Estimate gas limit
    const estimateGas = await web3.eth.estimateGas({
        to: recipientAddress,
        value: amountToSend
    });

    // Get gas price
    const gasPrice = await web3.eth.getGasPrice();

    // Prepare the transaction object
    const txObject = {
        nonce: web3.utils.toHex(nonce),
        to: recipientAddress,
        value: web3.utils.toHex(amountToSend),
        gasLimit: web3.utils.toHex(estimateGas),
        gasPrice: web3.utils.toHex(gasPrice),
        chainId: 1 // 1 for Ethereum mainnet
    };

Step 3. Sign a transaction

The following example code shows how to sign a transaction object.

Transaction object
const responseObject = await circleDeveloperSdk.signTransaction({
  walletID: '<wallet-id>',
  transaction: txObject, // Pass the transaction object
});

If you have created Programmable Wallets on an EVM-compatible chain such as Ethereum, Polygon, Avalanche, or Arbitrum, an EVM wallet created under the same wallet set maps to the same addresses.

In these cases, it is extremely important that you do not use the EVM wallet to sign transactions for existing Programmable Wallets on those chains; for example, sign transaction with chainID = 137 signs MATIC transaction.

Your Programmable Wallet transactions will be stuck and you are responsible for any resulting consequences.

Sign Transactions on EVM chains

Prerequisites

Step 1. Create EVM wallets

Step 2. Build transactions

Step 3. Sign a transaction