Hardhat

Hardhat 3 is a development environment for compiling, testing, deploying, and verifying smart contracts. You can start with the Monad template or add Monad to an existing Hardhat 3 project.

Hardhat 3 requires Node.js v22.13.0 or later.

Choose one setup path:

New project: Clone the Monad template and work inside the cloned repository.
Existing project: Do not clone the template into your project. Merge only the configuration shown below into your existing hardhat.config.ts.

Start with the Monad template

The Monad Hardhat 3 template includes:

Monad Testnet and Mainnet network configuration
Foundry-compatible Solidity tests and TypeScript tests using node:test
Viem for TypeScript interactions
Hardhat Ignition deployment modules
Sourcify and MonadScan contract verification

Clone and test the template:

git clone https://github.com/monad-developers/hardhat3-monad.git
cd hardhat3-monad
npm install
npx hardhat test

See the template’s README for local, Testnet, and Mainnet deployment commands.

Configure an existing Hardhat 3 project

Merge the following compiler and network settings into your hardhat.config.ts. Keep any plugins and other project-specific settings already in the file.

import { configVariable, defineConfig } from "hardhat/config";

export default defineConfig({
  solidity: {
    version: "0.8.28",
    settings: {
      evmVersion: "prague",
    },
  },
  networks: {
    monadTestnet: {
      type: "http",
      url: "https://testnet-rpc.monad.xyz",
      accounts: [configVariable("PRIVATE_KEY")],
      chainId: 10143,
    },
    monadMainnet: {
      type: "http",
      url: "https://rpc.monad.xyz",
      accounts: [configVariable("PRIVATE_KEY")],
      chainId: 143,
    },
  },
});

Never put a private key directly in hardhat.config.ts or commit it to version control. Provide PRIVATE_KEY through Hardhat’s configuration variable system, using the PRIVATE_KEY environment variable or the Hardhat keystore.

The prague EVM target is required when compiling contracts for Monad. For the canonical RPC URLs, chain IDs, and explorer URLs, see Network Information and Network Information - Testnet. Confirm the updated project still compiles and passes its tests:

npx hardhat compile
npx hardhat test

Introduction

Developer Essentials

Tooling and Infrastructure

Reference

Guides

Resources

Start with the Monad template

Configure an existing Hardhat 3 project

Deploy and verify

​Start with the Monad template

​Configure an existing Hardhat 3 project

​Deploy and verify

Start with the Monad template

Configure an existing Hardhat 3 project

Deploy and verify