EVM Signing

Sign EVM transactions using ethers.js, viem, or wagmi

Overview

EVM transactions returned by the Yield.xyz API can be signed using any Ethereum-compatible library. Below you’ll find examples for the three most popular options.

ethers.js

ethers.js

ethers.js is one of the most widely adopted Ethereum libraries, offering a clean API for wallets, providers, and contract interaction.

Installation

npm install ethers

Signing a Transaction

import { ethers } from "ethers";

const provider = new ethers.JsonRpcProvider(process.env.RPC_URL);
const wallet = new ethers.Wallet(process.env.PRIVATE_KEY, provider);

async function signAndSend(unsignedTx) {
  const tx = await wallet.sendTransaction({
    to: unsignedTx.to,
    data: unsignedTx.data,
    value: unsignedTx.value ?? 0,
    gasLimit: unsignedTx.gasLimit,
  });

  const receipt = await tx.wait();
  console.log("Transaction hash:", receipt.hash);
  return receipt;
}

ethers.Wallet handles nonce management and gas estimation automatically when connected to a provider.

viem

viem

viem is a modern, type-safe alternative focused on performance and tree-shaking.

Installation

npm install viem

Signing a Transaction

import { createWalletClient, http } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import { mainnet } from "viem/chains";

const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);

const client = createWalletClient({
  account,
  chain: mainnet,
  transport: http(process.env.RPC_URL),
});

async function signAndSend(unsignedTx: {
  to: `0x${string}`;
  data: `0x${string}`;
  value?: bigint;
}) {
  const hash = await client.sendTransaction({
    to: unsignedTx.to,
    data: unsignedTx.data,
    value: unsignedTx.value ?? 0n,
  });

  console.log("Transaction hash:", hash);
  return hash;
}

viem provides full TypeScript inference — hover over any method for complete type information without leaving your editor.

wagmi

wagmi

wagmi is a React hooks library built on top of viem, ideal for front-end dApps that connect browser wallets.

Installation

npm install wagmi viem @tanstack/react-query

Signing a Transaction

import { useSendTransaction, useWaitForTransactionReceipt } from "wagmi";

function SignTransaction({ unsignedTx }) {
  const { data: hash, sendTransaction } = useSendTransaction();

  const { isLoading, isSuccess } = useWaitForTransactionReceipt({ hash });

  const handleSign = () => {
    sendTransaction({
      to: unsignedTx.to,
      data: unsignedTx.data,
      value: unsignedTx.value ?? 0n,
    });
  };

  return (
    <div>
      <button onClick={handleSign} disabled={isLoading}>
        {isLoading ? "Confirming…" : "Sign & Send"}
      </button>
      {isSuccess && <p>Transaction confirmed: {hash}</p>}
    </div>
  );
}

wagmi delegates signing to the user’s connected wallet (MetaMask, WalletConnect, etc.), so you never handle private keys directly in the browser.