Custom SuperchainERC20 tokens

Overview

This guide explains how to modify the behavior of SuperchainERC20 (opens in a new tab) contracts to create custom tokens that can then be bridged quickly and safely using the SuperchainTokenBridge (opens in a new tab) contract (once interop is operational). For more information on how it works, see the explainer.

To ensure fungibility across chains, SuperchainERC20 assets must have the same contract address on all chains. This requirement abstracts away the complexity of cross-chain validation. Achieving this requires deterministic deployment methods. There are many ways to do this (opens in a new tab). Here we will use the SuperchainERC20 Starter Kit.

What you'll do

• Use the SuperchainERC20 Starter Kit to deploy tokens with your custom code.

What you'll learn

• How to deploy custom ERC-20 tokens on different chains at the same address so that they can be bridged with the SuperchainTokenBridge (opens in a new tab) contract.

Prerequisites

Before starting this tutorial, ensure your development environment meets the following requirements:

Technical knowledge

• Understanding of smart contract development
• Familiarity with blockchain concepts
• Familiarity with standard SuperchainERC20 deployments.

Development environment

• Unix-like operating system (Linux, macOS, or WSL for Windows)
• Git for version control

Required tools

The tutorial uses these primary tools:

• Foundry: For sending transactions to blockchains.

Step by step explanation

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.25;
 
import {SuperchainERC20} from "./SuperchainERC20.sol";
import {Ownable} from "@solady/auth/Ownable.sol";
 
contract CustomSuperchainToken is SuperchainERC20, Ownable {
    string private _name;
    string private _symbol;
    uint8 private immutable _decimals;
 
    constructor(address owner_, string memory name_, string memory symbol_, uint8 decimals_) {
        _name = name_;
        _symbol = symbol_;
        _decimals = decimals_;
 
        _initializeOwner(owner_);
    }
 
    function name() public view virtual override returns (string memory) {
        return _name;
    }
 
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }
 
    function decimals() public view override returns (uint8) {
        return _decimals;
    }
 
    function mintTo(address to_, uint256 amount_) external onlyOwner {
        _mint(to_, amount_);
    }
 
    function faucet() external {
        _mint(msg.sender, 10**_decimals);
    }
}

    function faucet() external {
        _mint(msg.sender, 10**_decimals);
    }

pnpm contracts:deploy:token

How does this work?

To allow for superchain interoperability, an ERC-20 token has to implement ERC-7802 (opens in a new tab). You can either use the SuperchainERC20 implementation (opens in a new tab), or write your own.

For more details see the explainer.

Next steps

• Use the SuperchainERC20 Starter Kit to deploy your token across the Superchain.
• Explore the SuperchainERC20 specifications (opens in a new tab) for in-depth implementation details.
• Review the Superchain Interop Explainer for answers to common questions about interoperability.