Deploy with Hardhat

This guide walks you through setting up Hardhat and deploying a smart contract to Mersennet testnet (Chain ID 7919).

Prerequisites

• Node.js 18+ and npm
• A funded wallet (get testnet PRIM from the faucet)

Installation

Create a new project or use an existing one:

mkdir my-prime-dapp && cd my-prime-dapp
npm init -y
npm install --save-dev hardhat @nomicfoundation/hardhat-toolbox
npx hardhat init

Select Create a TypeScript project when prompted.

Network Configuration

Add Mersennet to your hardhat.config.ts:

import { HardhatUserConfig } from "hardhat/config";
import "@nomicfoundation/hardhat-toolbox";

const config: HardhatUserConfig = {
  solidity: "0.8.20",
  networks: {
    prime: {
      url: "http://46.225.30.187:8545",
      chainId: 7919,
      accounts: process.env.PRIVATE_KEY ? [process.env.PRIVATE_KEY] : [],
    },
  },
};

export default config;

HttpNetworkConfig

Mersennet uses standard JSON-RPC. If you encounter issues with gas estimation or fee history (e.g., eth_feeHistory is not supported), you may need to add httpHeaders or adjust timeout in the network config. For deployment, the default config works with eth_sendTransaction.

Sample ERC-20 Contract

Create contracts/MyToken.sol:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract MyToken is ERC20 {
    constructor(uint256 initialSupply) ERC20("MyToken", "MTK") {
        _mint(msg.sender, initialSupply * 10 ** decimals());
    }
}

Install OpenZeppelin:

npm install @openzeppelin/contracts

Deployment Script

Create scripts/deploy.ts:

import { ethers } from "hardhat";

async function main() {
  const [deployer] = await ethers.getSigners();
  console.log("Deploying with account:", deployer.address);
  console.log("Account balance:", (await ethers.provider.getBalance(deployer.address)).toString());

  const MyToken = await ethers.getContractFactory("MyToken");
  const token = await MyToken.deploy(1_000_000); // 1M tokens
  await token.waitForDeployment();

  const address = await token.getAddress();
  console.log("MyToken deployed to:", address);
}

main()
  .then(() => process.exit(0))
  .catch((error) => {
    console.error(error);
    process.exit(1);
  });

Deploy to Mersennet

1. Set your private key (never commit this):

export PRIVATE_KEY="0x_your_private_key_here"

2. Fund your wallet from the faucet.

3. Run the deployment:

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

Expected output:

Deploying with account: 0x...
Account balance: 1000000000000000000
MyToken deployed to: 0x...

Verify Deployment

Query the deployed contract:

npx hardhat console --network prime

const token = await ethers.getContractAt("MyToken", "0xYourDeployedAddress");
const name = await token.name();
const supply = await token.totalSupply();
console.log(name, supply.toString());

Or use the block explorer to view the transaction and contract.

Troubleshooting

Issue	Solution
eth_feeHistory not supported	Mersennet does not support EIP-1559 fee history. Use --legacy or ensure your tooling uses legacy transactions.
Gas estimation fails	Try increasing gasLimit in the deployment script or use a fixed value (e.g., 3000000).
Connection refused	Ensure the RPC URL http://46.225.30.187:8545 is reachable from your network.
Insufficient funds	Get testnet PRIM from the faucet.