Polychain

A multi-chain cryptocurrency checkout platform that enables simple link-based transfers and embeddable merchant widgets across multiple blockchain networks.

Demo

Watch the platform in action: https://www.loom.com/share/133fea097d354ea6ae44d82c86f5bdb8?sid=33a8f195-685e-4dd9-a39c-ba4a80c879df

Overview

Polychain is a comprehensive cryptocurrency payment platform that simplifies cross-chain transactions and provides merchants with easy-to-integrate payment solutions. The platform supports multiple blockchain networks including Ethereum, Solana, Polygon, Bitcoin, and DeSo, enabling users (consumers and merchants both) to send and receive payments through simple, shareable links.

Key Features

Multi-Chain Support

• Ethereum (ETH): Full support for Ethereum mainnet transactions
• Solana (SOL): Native Solana blockchain integration
• Polygon (MATIC): Layer 2
• Bitcoin (BTC): QR code-based Bitcoin payments
• DeSo: Social blockchain integration

Core Functionality

• Link-Based Payments: Generate your custom crypto home page, which you can share with others (as opposed to long addresses), who can then use that to send crypto to you.
• Embeddable Widgets: Merchant integration tools for websites and applications
• NFT Showcase: Display and manage NFT collections
• Wallet Integration: Support for MetaMask, WalletConnect, and Phantom wallets
• Real-time Exchange Rates: Live cryptocurrency price feeds via Coinbase API
• User Profiles: Customizable user profiles with bio and profile pictures

Technical Features

• Merkle Tree Distribution: Efficient token distribution system
• Promo Code System: Built-in promotional code functionality
• JWT Authentication: Secure user authentication and session management
• Responsive Design: Mobile-first, responsive user interface
• Real-time Notifications: Toast notifications for transaction status

Architecture

Frontend

• Framework: Next.js 12 with React 17
• Styling: Tailwind CSS with custom components
• State Management: React Context API
• Wallet Integration: Web3Modal, WalletConnect, MetaMask
• UI Components: Headless UI, Heroicons

Backend

• Runtime: Node.js with TypeScript
• Framework: Express.js
• Database: MongoDB with Mongoose ODM
• Authentication: JWT with cookie-based sessions
• Blockchain Integration: Ethers.js, Solana Web3.js
• API Integration: Coinbase API for exchange rates

Smart Contracts

• ERC-20 Token: Standard Ethereum token implementation
• Merkle Distributor: Gas-efficient token distribution contract
• OpenZeppelin: Security-audited contract libraries

Infrastructure

• Cloud Platform: AWS with EC2 Auto Scaling
• Containerization: Docker for consistent deployments
• CI/CD: Automated deployment pipelines
• Monitoring: Prometheus and Grafana for system monitoring
• CDN: CloudFront for global content delivery

Project Structure

Polychain/
├── frontend/          # Next.js React application
│   ├── pages/         # Application routes and components
│   ├── lib/           # Utility functions and blockchain integrations
│   └── public/        # Static assets and contract ABIs
├── backend/           # Node.js Express API server
│   ├── src/           # TypeScript source code
│   ├── models/        # MongoDB data models
│   └── utils/         # Server-side utilities
├── erc20/             # Smart contract implementations
│   └── contracts/     # Solidity smart contracts
└── embed/             # Embeddable widget system
    └── src/           # Widget JavaScript bundle

Getting Started

Prerequisites

• Node.js 18.0.0 or higher
• MongoDB database
• Ethereum wallet (Phantom recommended)
• Solana wallet (Phantom recommended)

Installation

1. Clone the repository

   git clone https://github.com/yourusername/polychain.git
   cd polychain

2. Install frontend dependencies

   cd frontend
   npm install

3. Install backend dependencies

   cd ../backend
   npm install

4. Install smart contract dependencies

   cd ../erc20
   npm install

5. Install embed widget dependencies

   cd ../embed
   npm install

Environment Setup

1. Backend Environment Variables Create a .env file in the backend directory:

   MONGODB_URI=your_mongodb_connection_string
   COOKIE_SECRET=your_jwt_secret
   NODE_ENV=development
   JWT_SECRET=123123
   TWITTER_ACCESS_TOKEN=your_twitter_api_token
   ETHERSCAN_API_KEY=your_etherscan_api_key
   POLYGONSCAN_API_KEY=your_polygonscan_api_key

2. Frontend Environment Variables Create a .env file in the frontend directory:

   NEXT_PUBLIC_BACKEND_URL=http://localhost:3001
   NEXT_PUBLIC_NFTPORT_API_KEY=your_nftport_api_key_here

Running the Application

1. Start the backend server

   cd backend
   npm run start

2. Start the frontend development server

   cd frontend
   npm run dev

3. Build the embed widget

   cd embed
   npm run build

The application will be available at http://localhost:3000 and the API at http://localhost:3001.

Security

• JWT-based authentication with secure cookie storage
• Input validation and sanitization
• Rate limiting on API endpoints
• Secure wallet integration with signature verification
• Smart contract security audits

Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Support

For support and questions:

• Create an issue in the GitHub repository
• Contact the development team
• Check the documentation wiki

Built with ❤️ by the Spindl team