Zap

• Backend never touches funds — only stores payment intents
• Frontend executes routes — using LI.FI SDK with user's wallet
• Transparent fees — all gas/bridge fees shown upfront

Zap is a non-custodial DeFi payments app that lets users send and receive money across chains with zero friction. Users create payment links or split expenses, and pay using any token on any EVM chain. Zap uses LI.FI to automatically route liquidity, handling swaps and bridges in a single transaction so recipients always receive USDC. The app abstracts away gas fees, chain selection, and DeFi complexity, turning fragmented blockchain liquidity into a simple, reliable payment experience.

Zap is built as a non-custodial, intent-based DeFi app with a lightweight web frontend and a Node.js backend. The frontend is built with React, TypeScript, Tailwind, and wagmi/RainbowKit for wallet connectivity. Users create payment intents (links or splits) that encode amount, recipient, and settlement token (USDC). The backend exposes simple APIs to create and resolve intents and integrates with LI.FI s API/SDK to fetch optimal cross-chain routes. When a user pays, Zap uses LI.FI to orchestrate swap and bridge routes across supported EVM chains, abstracting gas fees, chain selection, and liquidity fragmentation from the user. Transactions are executed directly from the user's wallet, keeping Zap fully non-custodial.

A notable hack is the pay-from-anywhere flow: users can pay with any supported token on any chain, while recipients always receive USDC, with all routing handled automatically in a single user action.