Send - Ethereum Transaction DApp

A modern, decentralized application for sending Ethereum transactions on the blockchain. Built with React, Tailwind CSS, and Hardhat.

🚀 Features

• Secure Wallet Integration - Connect with MetaMask wallet
• Send Transactions - Transfer ETH with messages and keywords
• Transaction History - View all your blockchain transactions
• Modern UI - Beautiful, responsive design with Tailwind CSS
• Sepolia Testnet - Deployed on Ethereum Sepolia testnet
• Real-time Updates - Transactions update automatically

📁 Project Structure

Bblockchainnn/
├── Client/          # Frontend React application
│   ├── src/
│   │   ├── Components/    # React components
│   │   ├── context/        # Transaction context
│   │   └── utils/          # Utilities and constants
│   └── package.json
│
└── Contract/       # Smart contract (Hardhat)
    ├── contracts/   # Solidity contracts
    ├── scripts/     # Deployment scripts
    └── package.json

🛠️ Tech Stack

Frontend

• React 19 - UI library
• Vite - Build tool
• Tailwind CSS - Styling
• Ethers.js - Ethereum library

Smart Contract

• Solidity 0.8.28 - Smart contract language
• Hardhat - Development environment
• Ethers.js - Ethereum interactions

📦 Installation

Prerequisites

• Node.js (v18 or higher)
• MetaMask browser extension
• Git

Frontend Setup

cd Client
npm install
npm run dev

The frontend will run on http://localhost:3000

Smart Contract Setup

cd Contract
npm install

# Create .env file from example
cp .env.example .env

# Edit .env and add your Alchemy URL and Private Key
# Then compile
npx hardhat compile

Important: Create a .env file in the Contract/ directory with:

• ALCHEMY_URL - Your Alchemy API endpoint for Sepolia
• PRIVATE_KEY - Your wallet's private key for deployment

See .env.example for the template.

🚀 Deployment

Deploy Contract to Sepolia

cd Contract
npx hardhat run scripts/deploy.ts --network sepolia

After deployment, update the contract address in Client/src/utils/constants.ts

🔧 Configuration

Environment Variables

Create a .env file in the Contract/ directory:

# Copy the example file
cp Contract/.env.example Contract/.env

# Edit with your values
nano Contract/.env  # or use your preferred editor

Required variables:

• ALCHEMY_URL - Your Alchemy API endpoint (get from https://www.alchemy.com/)
• PRIVATE_KEY - Your wallet's private key for deployment (without 0x prefix)

Security Note: Never commit .env files to git. They are already in .gitignore.

Contract Address

Update the contract address in Client/src/utils/constants.ts after deployment:

export const ContractAddress = "YOUR_DEPLOYED_CONTRACT_ADDRESS";

Network Configuration

The app is configured for Sepolia testnet. Make sure MetaMask is connected to Sepolia.

📝 Usage

1. Connect Wallet

   • Click "Connect Wallet" button
   • Approve MetaMask connection
   • Ensure you're on Sepolia testnet

2. Send Transaction

   • Fill in recipient address
   • Enter amount in ETH
   • Add keyword and message
   • Click "Send Now"
   • Confirm transaction in MetaMask

3. View Transactions

   • All transactions are displayed in the Recent Transactions section
   • Transactions are fetched automatically from the blockchain

🌐 Network

• Network: Sepolia Testnet
• Chain ID: 11155111
• Contract Address: 0x9edCe95b7eBeb2eFbE393c7Ea7280C1234c69c71

📄 Smart Contract

The Transaction.sol contract provides:

• addToBlockchain() - Send ETH with message and keyword
• getAllTransactions() - Retrieve all transactions
• getTransactionCount() - Get total transaction count

🔒 Security

• All transactions require MetaMask approval
• Network validation ensures Sepolia testnet usage
• Input validation on all form fields
• Balance checks before transactions

🧪 Testing

Test on Sepolia

1. Get Sepolia ETH from a faucet:

   • https://sepoliafaucet.com/
   • https://faucet.quicknode.com/ethereum/sepolia
   • https://www.alchemy.com/faucets/ethereum-sepolia

2. Connect MetaMask to Sepolia testnet

3. Send test transactions

📚 Scripts

Frontend

• npm run dev - Start development server
• npm run build - Build for production
• npm run preview - Preview production build

Contract

• npx hardhat compile - Compile contracts
• npx hardhat run scripts/deploy.ts --network sepolia - Deploy to Sepolia

🤝 Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Submit a pull request

📄 License

ISC

👤 Author

Built with ❤️ for decentralized transactions

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Note: This is a testnet application. Do not use with mainnet ETH or real funds.