Alchemy Local Dev Loop

Overview

Local Web3 development workflow using Alchemy as the RPC provider with Hardhat for local testing, Sepolia testnet for staging, and hot-reload for rapid iteration.

Prerequisites

• Completed alchemy-install-auth setup
• Node.js 18+
• Alchemy API key with Sepolia testnet app

Instructions

Step 1: Initialize Hardhat Project with Alchemy

mkdir web3-project && cd web3-project
npm init -y
npm install --save-dev hardhat @nomicfoundation/hardhat-toolbox
npm install alchemy-sdk dotenv
npx hardhat init  # Select TypeScript project

Step 2: Configure Hardhat with Alchemy RPC

// hardhat.config.ts
import { HardhatUserConfig } from 'hardhat/config';
import '@nomicfoundation/hardhat-toolbox';
import 'dotenv/config';

const config: HardhatUserConfig = {
  solidity: '0.8.24',
  networks: {
    hardhat: {
      forking: {
        url: `https://eth-mainnet.g.alchemy.com/v2/${process.env.ALCHEMY_API_KEY}`,
        blockNumber: 19000000,  // Pin block for reproducible tests
      },
    },
    sepolia: {
      url: `https://eth-sepolia.g.alchemy.com/v2/${process.env.ALCHEMY_API_KEY}`,
      accounts: process.env.DEPLOYER_PRIVATE_KEY ? [process.env.DEPLOYER_PRIVATE_KEY] : [],
    },
  },
};

export default config;

Step 3: Alchemy-Powered Test Helper

// test/helpers/alchemy-helper.ts
import { Alchemy, Network } from 'alchemy-sdk';

const alchemy = new Alchemy({
  apiKey: process.env.ALCHEMY_API_KEY,
  network: Network.ETH_SEPOLIA,
});

export async function getTestnetBalance(address: string): Promise<string> {
  const balance = await alchemy.core.getBalance(address);
  return (parseInt(balance.toString()) / 1e18).toFixed(4);
}

export async function waitForTransaction(txHash: string): Promise<any> {
  return alchemy.core.waitForTransaction(txHash, 1, 60000);
}

export { alchemy };

Step 4: Development Scripts

{
  "scripts": {
    "dev": "npx hardhat node --fork https://eth-mainnet.g.alchemy.com/v2/${ALCHEMY_API_KEY}",
    "test": "npx hardhat test",
    "test:watch": "npx hardhat test --watch",
    "deploy:sepolia": "npx hardhat run scripts/deploy.ts --network sepolia",
    "verify": "npx hardhat verify --network sepolia"
  }
}