💸 Payroll DApp using Hardhat, Ganache, React-TS, Node.js & Express

This project is a full-stack decentralized payroll system that allows employers to add employees and send them crypto-based salaries using Ethereum smart contracts. Built with:

• Solidity + Hardhat (Smart Contracts)
• Ganache CLI (Local blockchain)
• Node.js + Express (Backend API)
• React + TypeScript (Frontend)

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📁 Project Structure

payroll-dapp/
├── backend/
│ ├── src/
│ ├── .env
│ ├── server.ts
│ └── package.json
├── contracts/
│ ├── Payroll.sol
│ └── deploy.js
├── frontend/
│ ├── src/
│ ├── public/
│ ├── .env
│ ├── vite.config.ts
│ └── package.json
├── hardhat.config.js
├── README.md
└── .env

Create & Compile

npx hardhat npx hardhat compile

Run Ganache (local blockchain) npm install -g ganache ganache

Deploy Contracts Locally npx hardhat run contracts/deploy.js --network localhost

Navigate to backend folder cd backend

npm install express dotenv cors ethers npm install -D typescript ts-node-dev @types/express @types/node

Setup .env PORT=5000 CONTRACT_ADDRESS=your_local_contract_address PRIVATE_KEY=your_wallet_private_key RPC_URL=http://127.0.0.1:8545 VITE_BACKEND_URL=http://localhost:5000 VITE_CONTRACT_ADDRESS=your_local_contract_address

npx ts-node-dev src/server.ts

Install Dependencies

npm install npm install ethers axios npm install -D @types/react @types/node

Commands Summary

Task	Command
Compile contracts	npx hardhat compile
Run Ganache	ganache
Deploy contract	npx hardhat run deploy.js --network localhost
Start backend API	cd backend && npx ts-node-dev src/server.ts
Start frontend	cd frontend && npm run dev