⚡ VoidTx - Batch Payment System

Send crypto to multiple recipients in ONE transaction.

What It Does

VoidTx lets you pay up to 100 people in a single transaction instead of sending 100 separate transactions. If any payment fails, it continues with the rest and refunds you automatically.

Use Cases: Payroll, airdrops, prize distributions, DAO payments

FlashPay.-demo.mp4

Key Features

• 🛡️ Fault Tolerant - Failed payments don't stop the batch
• 💰 Auto Refunds - Failed amounts returned automatically
• 📊 Production Ready - 20+ tests passing, REST API included
• 🔗 Multi-chain Support - Monad Testnet, Sepolia, Ethereum, Polygon, Arbitrum, etc.
• 🆕 Gasless Transactions - ERC-4337 Account Abstraction for zero gas fees

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📁 Project Structure

voidtx/
├── contracts/
│   ├── VoidTx.sol               # Main batch payment contract
│   └── test/
│       └── RejectPayment.sol     # Test helper contract
├── scripts/
│   ├── deploy.js                 # Deployment script for Monad Testnet
│   └── testTransaction.js        # Test batch payments with sample data
├── backend/
│   ├── server.js                 # Express API server
│   ├── aaRoutes.js               # ERC-4337 Account Abstraction endpoints
│   ├── accountAbstractionService.js # Gasless transaction service
│   └── eventReader.js            # Event monitoring utility
├── frontend-utils/
│   ├── VoidTxApp.jsx            # Main React application
│   ├── BatchPaymentForm.jsx      # Payment form component
│   ├── WalletConnector.jsx       # Wallet connection utilities
│   ├── csvParser.js              # CSV upload processor
│   ├── templates.js              # Payment templates
│   └── dashboard.js              # Analytics dashboard (removed)
├── deployments/                  # Deployment artifacts (auto-generated)
├── hardhat.config.js             # Hardhat configuration
├── package.json                  # Dependencies
└── .env.example                  # Environment variables template

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🚀 Quick Start

# Install dependencies
npm install

# Setup environment
cp .env.example .env
# Edit .env with your private key and RPC URL

# Deploy to Monad Testnet
npm run deploy-monad

# Test with sample transactions
npm run test-transaction-monad

# Start API server
npm run backend

# Start frontend (in a new terminal)
npm run dev

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Features:

• Validates inputs (max 100 recipients, min 0.0001 ETH per payment)
• Continues processing even if individual payments fail
• Auto-refunds failed amounts
• Emits detailed events for tracking

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Core Endpoints

• GET /health - Health check
• GET /api/stats - Contract statistics
• GET /api/events/:type - Query payment events
• POST /api/estimate - Estimate batch cost
• GET /api/transaction/:hash - Transaction status
• POST /api/qr - Generate QR code

Account Abstraction (Gasless Transactions)

• GET /api/aa/health - AA service health check
• POST /api/aa/account/create - Create Smart Account
• GET /api/aa/account/:userId - Get Smart Account address
• GET /api/aa/account/:userId/balance - Check balance
• POST /api/aa/transaction/gasless-batch - Execute gasless payment
• POST /api/aa/demo/gasless-payment - Demo full flow

Example:

curl http://localhost:3001/api/stats

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🧪 Testing

npm test  # Run all tests

Tests cover:

• Batch payments (5-10 recipients)
• Error handling
• Event emission
• Gas estimation
• Edge cases

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🔐 Environment Setup

Create .env file:

# Monad Testnet Configuration
MONAD_RPC_URL=https://testnet.monadvision.com/rpc
PRIVATE_KEY=your_wallet_private_key

# ERC-4337 Account Abstraction (for gasless transactions)
PIMLICO_API_KEY=your_pimlico_api_key
BUNDLER_OWNER_PRIVATE_KEY=private_key_for_bundler

# Backend Server Configuration
PORT=3001
CONTRACT_ADDRESS=deployed_contract_address
NETWORK=monadTestnet

Get free Monad Testnet setup:

1. RPC URL: https://testnet.monad.xyz/rpc
2. Test ETH: Request from Monad Discord

For Gasless Transactions:

1. Get Pimlico API key: https://dashboard.pimlico.io/
2. Generate a new private key for BUNDLER_OWNER_PRIVATE_KEY

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🛠️ Commands

npm install              # Install dependencies
npm run compile         # Compile contract
npm run deploy-monad    # Deploy to Monad Testnet
npm run deploy          # Deploy to Sepolia
npm test                # Run tests
npm run backend         # Start API server
npm run dev             # Start frontend
npm run check-balance   # Check wallet balance
npm run test-transaction # Send test batch

🆕 Gasless Transactions (ERC-4337)

VoidTx supports gasless transactions using Account Abstraction:

1. Users create Smart Accounts (ERC-4337 compatible)
2. Transactions are sponsored by a Paymaster (Pimlico)
3. No gas fees for end users
4. Fully decentralized and secure

Benefits:

• Zero gas fees for users
• Improved UX for onboarding
• Enterprise-grade security
• Compatible with all EVM chains

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📱 Advanced Features

CSV Upload

Import recipient lists from CSV files for easy bulk payments.

Payment Templates

Predefined templates for common scenarios:

• Split Equally
• Fixed Amount

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🌐 Supported Networks

Network	Chain ID	RPC URL	Explorer
Monad Testnet	10143	https://testnet.monad.xyz/rpc	https://testnet.monadvision.com
Sepolia	11155111	https://rpc.sepolia.org	https://sepolia.etherscan.io

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📄 License

MIT

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