EVM Wallet Authentication

Authenticate using Ethereum-compatible wallets like MetaMask, WalletConnect, or other EVM wallets.

Prerequisites

User has an EVM wallet installed (MetaMask, etc.)
User has an Ethereum address

How It Works

EVM authentication allows users with Ethereum wallets to interact with Bako Safe on Fuel. The SDK handles the address conversion between EVM and Fuel formats.

Implementation with MetaMask

import { BakoProvider, TypeUser } from 'bakosafe';
 
async function authenticateWithMetaMask() {
  // Check if MetaMask is installed
  if (!window.ethereum) {
    throw new Error('MetaMask not installed');
  }
 
  // Request account access
  const accounts = await window.ethereum.request({
    method: 'eth_requestAccounts'
  });
  const evmAddress = accounts[0];
 
  // Step 1: Setup authentication
  const { code } = await BakoProvider.setup({
    address: evmAddress,
    provider: 'https://mainnet.fuel.network/v1/graphql',
    encoder: TypeUser.EVM
  });
 
  // Step 2: Sign the challenge with MetaMask
  const signature = await window.ethereum.request({
    method: 'personal_sign',
    params: [code, evmAddress]
  });
 
  // Step 3: Complete authentication
  const provider = await BakoProvider.authenticate({
    challenge: code,
    signature,
    encoder: TypeUser.EVM,
    address: evmAddress,
    serverUrl: 'https://api.bako.global'
  });
 
  return provider;
}

Using with ethers.js

import { BakoProvider, TypeUser } from 'bakosafe';
import { ethers } from 'ethers';
 
async function authenticateWithEthers() {
  // Connect to MetaMask
  const ethProvider = new ethers.BrowserProvider(window.ethereum);
  const signer = await ethProvider.getSigner();
  const evmAddress = await signer.getAddress();
 
  // Setup
  const { code } = await BakoProvider.setup({
    address: evmAddress,
    provider: 'https://mainnet.fuel.network/v1/graphql',
    encoder: TypeUser.EVM
  });
 
  // Sign
  const signature = await signer.signMessage(code);
 
  // Authenticate
  const provider = await BakoProvider.authenticate({
    challenge: code,
    signature,
    encoder: TypeUser.EVM,
    address: evmAddress,
    serverUrl: 'https://api.bako.global'
  });
 
  return provider;
}

Using with wagmi/viem

import { BakoProvider, TypeUser } from 'bakosafe';
import { useAccount, useSignMessage } from 'wagmi';
 
function useBakoEVMAuth() {
  const { address } = useAccount();
  const { signMessageAsync } = useSignMessage();
 
  async function authenticate() {
    if (!address) {
      throw new Error('Wallet not connected');
    }
 
    // Setup
    const { code } = await BakoProvider.setup({
      address,
      provider: 'https://mainnet.fuel.network/v1/graphql',
      encoder: TypeUser.EVM
    });
 
    // Sign
    const signature = await signMessageAsync({ message: code });
 
    // Authenticate
    const provider = await BakoProvider.authenticate({
      challenge: code,
      signature,
      encoder: TypeUser.EVM,
      address,
      serverUrl: 'https://api.bako.global'
    });
 
    return provider;
  }
 
  return { authenticate };
}

Address Conversion

The SDK provides utilities for converting between EVM and Fuel address formats:

import { AddressUtils } from 'bakosafe';
 
// Check if address is EVM format
const isEvm = AddressUtils.isEvm('0x742d35Cc6634C0532925a3b844Bc9e7595f8fE34');
 
// Convert Fuel address to EVM format
const evmAddress = AddressUtils.parseFuelAddressToEth(fuelAddress);

Supported EVM Wallets

Wallet	Support
MetaMask	Full
WalletConnect	Full
Coinbase Wallet	Full
Rainbow	Full
Trust Wallet	Full
Any EIP-1193 compatible wallet	Full

Signature Encoding

EVM signatures use a different encoding than Fuel signatures. The SDK handles this automatically through the SignatureType.Evm coder:

import { SignatureType } from 'bakosafe';
 
// SignatureType.Evm = 2
// Used internally for encoding EVM signatures

Next Steps

WebAuthn (Passkeys)Overview