erc1271_signer

Dart port of viem-style utilities for Ethereum: Coinbase Smart Wallet message signing, EIP-191 / EIP-712 hashing, and ERC-1271-compatible signatures.

Features

• Coinbase Smart Wallet (SCA) message signing compatible with viem and ERC-1271
• EIP-191 personal sign message hashing
• EIP-712 typed data hashing (replay-safe domain for Coinbase Smart Wallet)
• Supported chains: Base, Base Sepolia, Mainnet, Sepolia

Installation

Add to your pubspec.yaml:

dependencies:
  erc1271_signer: ^0.1.1

Then run:

dart pub get

Usage

Pass chain, privateKey, and message to get the ERC-1271 wrapped signature:

import 'package:erc1271_signer/erc1271_signer.dart';

void main() async {
  final signature = await signMessage(
    chainName: 'baseSepolia',
    privateKey: '0x_your_private_key',
    message: 'I hereby declare that I am the address owner.',
  );
  // Use signature with ERC-1271 / verify on-chain or with viem verifyMessage
  print(signature);
}

Chain names: base, baseSepolia, mainnet, sepolia.

For lower-level control (client, account, smart account), use the exported APIs: getChain, privateKeyToAccount, toCoinbaseSmartAccount, PublicClient, etc.

Example

See the example/ app:

cd example
dart pub get
dart run lib/main.dart

Edit example/lib/main.dart to set your chainName, privateKey, and message (use a test key only).

Verification

Signatures produced by this package can be verified with viem’s publicClient.verifyMessage() (ERC-1271 / ERC-6492) using the same chain, smart account address, message, and signature.