Deploy with Hardhat

This page shows how to deploy and verify a contract on Whitechain Sepolia using Hardhat. Whitechain Sepolia is a standard EVM network, so you add it by chain ID and RPC URL. Hardhat needs no Whitechain-specific plugin. It is for developers who work from the command line. Ready-made template: Hardhat in the Whitechain templates repository. The fastest path below clones it and deploys. The companion Foundry template is Foundry.

Fastest path

The Hardhat template is a finished project for Whitechain Sepolia: the network is configured, the contract and tests are in place, and the deploy script is written. You need Node.js 22 or later and a funded key. The walkthrough after this section builds the same project by hand, if you would rather see every step.

Get the Hardhat folder and install its dependencies.

npx degit whitechain-labs/templates/Hardhat whitechain-hardhat
cd whitechain-hardhat
npm install

Copy the environment file.
cp .env.example .env
Set PRIVATE_KEY to a throwaway key funded from the faucet. TESTNET_RPC_URL already points at the public endpoint. npm run compile and npm test both run before you fill anything in.
Deploy.
npm run deploy:testnet
The script prints the deployed address and its explorer URL.

Verify, using the address from step 3.

npx hardhat verify --network whitechainSepolia <contract_address>

The template registers the network as whitechainSepolia (chain ID 1874) and points verification at the Whitechain Blockscout explorer. Source: whitechain-labs/templates.

Hardhat publishes its own Agent Skill for AI coding assistants. Install it with npx skills add nomicfoundation/hardhat-skills for AI-guided help with Hardhat 3 workflows and migrations. Pair it with the whitechain-dev skill for the Whitechain-specific steps below.

Before you deploy

Node.js 22 or later and npm. Hardhat 3 requires Node.js 22 or newer.
A funded testnet account. Claim test WBT from the faucet.
The private key for that account. Use a throwaway key for testing.

1. Create a project

npm install --save-dev hardhat
npx hardhat --init

When prompted:

Prompt	Response
Which version of Hardhat?	Choose Hardhat 3 (recommended for new projects)
Where would you like to initialize the project?	Press Enter for the current directory
What type of project?	Choose A TypeScript Hardhat project using Node Test Runner and Viem
Would you like to change `package.json` to turn your project into ESM?	Enter `y`
Confirm dependency installation?	Press Enter

2. Set environment variables

npm install --save-dev dotenv

Create a .env file:

PRIVATE_KEY=0x_your_private_key_here

The key must include the 0x prefix. Hardhat rejects the network configuration without it. Add .env to .gitignore so you do not commit the key.

Never commit a private key, and never reuse a mainnet key for testing. Anyone with the key controls the funds.

3. Configure the network

Replace the contents of hardhat.config.ts with:

import type { HardhatUserConfig } from "hardhat/config";
import hardhatToolboxViem from "@nomicfoundation/hardhat-toolbox-viem";
import "dotenv/config";

const config: HardhatUserConfig = {
  plugins: [hardhatToolboxViem],
  solidity: "0.8.30",
  networks: {
    whitechainSepolia: {
      type: "http",
      url: "https://rpc.testnet.whitechain.io",
      accounts: [process.env.PRIVATE_KEY!],
      chainId: 1874,
    },
  },
  verify: {
    sourcify: {
      enabled: true,
    },
  },
};

export default config;

4. Add a contract

Create contracts/Storage.sol.

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.30;

contract Storage {
    uint256 number;

    function store(uint256 num) public {
        number = num;
    }

    function retrieve() public view returns (uint256) {
        return number;
    }
}

5. Add a deploy script

Create scripts/deploy.ts.

import { network } from "hardhat";

const { viem } = await network.create("whitechainSepolia");
const storage = await viem.deployContract("Storage");
console.log("Storage deployed to:", storage.address);

network.create("whitechainSepolia") opens a connection to the network defined in hardhat.config.ts. Passing the name makes the script explicit; network.create() with no argument uses whatever --network selects. Do not use network.connect(), which is deprecated in Hardhat 3 and will be removed. Hardhat 3 uses ESM with top-level await, so no main() wrapper is needed.

6. Deploy the contract

npx hardhat run scripts/deploy.ts --network whitechainSepolia

The contract address prints to the console. Copy it for verification.

7. Verify the contract

Storage takes no constructor arguments, so pass only the address.

npx hardhat verify --network whitechainSepolia <contract_address>

For a contract with constructor arguments, add them after the address.

Verify the result

Open the contract address on the explorer. The Contract tab shows the source code and a verified marker. hardhat verify submits to every verifier configured for the network, so the same source also lands on Sourcify.

If you deployed the Storage example unchanged, the explorer may show its source before you verify anything. That is a verified twin: the same bytecode is already verified at another address, so the explorer matches it. Hardhat then skips Blockscout and verifies only on Sourcify, and your address stays unverified in its own right. Record it with npx hardhat verify blockscout --force --network whitechainSepolia <contract_address>. Your own contracts have unique bytecode, so they have no twin and the plain command covers both verifiers.

Wallet

Dapps

Deploy

Bridge

Block Explorer

Ecosystem

Fastest path

Before you deploy

1. Create a project

2. Set environment variables

3. Configure the network

4. Add a contract

5. Add a deploy script

6. Deploy the contract

7. Verify the contract

Verify the result

​Fastest path

​Before you deploy

​1. Create a project

​2. Set environment variables

​3. Configure the network

​4. Add a contract

​5. Add a deploy script

​6. Deploy the contract

​7. Verify the contract

​Verify the result

​Related

Fastest path

Before you deploy

1. Create a project

2. Set environment variables

3. Configure the network

4. Add a contract

5. Add a deploy script

6. Deploy the contract

7. Verify the contract

Verify the result

Related