X402 STARTER KIT

Summary from the TLDR Crypto newsletter

The x402 starter kit allows developers to build paid APIs requiring USDC micropayments before processing requests, with three core components: an Express server, the Merchant Executor for payment verification/settlement, and a service demonstrating OpenAI/EigenAI integration. The kit supports both facilitator-based settlement and local direct settlement modes across multiple networks, including Base, Polygon, Avalanche, and Solana, with payment verification using EIP-3009 authorization signatures. Developers can deploy custom frontends and can configure AI providers (OpenAI or EigenAI), network parameters, and settlement modes through environment variables, with the full payment flow handling 402 responses, signature verification, blockchain settlement, and service execution.