SwapBridge Pay

SwapBridge Pay is a lightweight cross-chain payment relay that enables users to seamlessly swap tokens on the Ethereum blockchain using the 1inch Fusion or Swap API and forward the equivalent value to a Stellar wallet. Designed for simplicity and speed, the application allows users to connect their MetaMask wallet on the Sepolia testnet, select a token swap (e.g., ETH to USDC), and enter a recipient’s Stellar address. The backend performs the swap through 1inch and then uses the Stellar SDK to transfer the funds to the destination address. Built entirely with Next.js, TypeScript, and standard web3 libraries, the project avoids the complexity of smart contracts or Rust, relying instead on API and SDK interactions. SwapBridge Pay demonstrates a practical and cost-efficient way to enable cross-chain payments, ideal for remittances, DeFi payouts, and crypto-to-fiat off-ramps.

SwapBridge Pay is built using a full-stack TypeScript-based architecture with a focus on simplicity, speed, and cross-chain functionality. The frontend is developed in Next.js with Tailwind CSS, providing a responsive dark-themed UI where users can connect their MetaMask wallet on the Sepolia Ethereum testnet, specify the amount and token to swap, and enter a recipient’s Stellar address. The backend is a Node.js Express server that handles swap operations using the 1inch API, constructs and signs Ethereum transactions via the ethers.js library, and monitors for transaction confirmation. Once the swap is complete, the backend calculates the equivalent value and uses the Stellar SDK to create and submit a payment transaction on the Stellar testnet to the given address. The app relies entirely on REST APIs and SDKs without deploying any smart contracts, making it fast to develop and easy to maintain. All sensitive data, such as Stellar secret keys or API keys, are securely managed through environment variables. The result is a smooth and developer-friendly cross-chain swap and payment experience.