If you are using Web3Auth to sign transactions, you will need to configure a Web3Auth provider and get the signer from this provider.

Configuring Web3Auth

First, see how to configure Web3Auth at Web3Auth Quickstart.

Live Tutorial

You can see a tutorial using Web3Auth here: Web3Auth Demo.

Integration

Here is an example that uses an Openlogin adapter.

import { Web3Auth } from "@web3auth/modal";
import { OpenloginAdapter } from "@web3auth/openlogin-adapter";

const chainConfig = {
  chainNamespace: CHAIN_NAMESPACES.EIP155,
  chainId: "0x1",
  rpcTarget: "https://api.stackup.sh/v1/node/API_KEY",
  displayName: "Ethereum Mainnet",
  blockExplorer: "https://etherscan.io",
  ticker: "ETH",
  tickerName: "Ethereum",
};

const web3auth = new Web3AuthNoModal({...});

const privateKeyProvider = new EthereumPrivateKeyProvider({
  config: { chainConfig },
});

const openloginAdapter = new OpenloginAdapter({
  privateKeyProvider,
  adapterSettings: {...},
  mfaSettings: {...},
  loginSettings: {...},
});
web3auth.configureAdapter(openloginAdapter);

const web3authProvider = await web3auth.connectTo(
  WALLET_ADAPTERS.OPENLOGIN,
  {
    loginProvider: "google",
  }
);

// Initialize builder with Web3Auth signer
const signer = web3authProvider.getSigner();
var builder = await Presets.Builder.SimpleAccount.init(signer, rpcUrl);
const address = builder.getSender();
console.log(Account address: ${address});