TrustPay

TrustPay is a Web3 payment system that brings card-on-file experiences to crypto. Users scan a merchant QR code, pay once via WalletConnect, and can choose to whitelist the merchant. Once trusted, future payments become instant and require no additional signatures. Each whitelisted merchant is linked to programmable spending rules, including maximum amount, frequency limits, and default payment token. ENS is used to provide human-readable merchant identities, improving trust and usability. The system eliminates repetitive signing while preserving self-custody and user control. Payments can optionally be executed privately using Unlink, ensuring sensitive financial data is not exposed on-chain. TrustPay redefines crypto payments by combining seamless UX with programmable permissions, enabling a secure and intuitive alternative to traditional card-on-file systems like Apple Pay.

TrustPay is built on Next.js 14 with wagmi v2 and WalletConnect's Web3Modal for wallet connectivity. The core innovation is a context-aware payment engine: on first payment, users sign an ERC20 approve() transaction via WalletConnect, authorizing a backend relayer to spend up to their defined limit. Subsequent payments are executed server-side via a Vercel API route using viem's writeContract with transferFrom(),zero popups, zero friction. ENS resolution is handled natively through wagmi's useEnsAddress hook on Ethereum mainnet. Merchant whitelisting stores programmable spending rules (max amount, frequency, expiration, privacy mode) in React context. The private payment toggle integrates Unlink for on-chain privacy. All transactions are verified on Ethereum Sepolia with links to Etherscan. The approve + relayer pattern mirrors how real DeFi protocols like Uniswap handle gasless UX without compromising self-custody.