x402 Deep Dive: A Payment Standard for the Internet

x402 is a blockchain-based payment standard that enables micropayments for web services using the HTTP 402 status code. It works through a stateless flow involving buyers, sellers, and optional facilitators that verify payments. The standard uses EIP-3009 tokens like USDC and EIP-712 signatures for payment authorization. Implementation is straightforward using x402-express middleware for servers and x402-fetch for clients, with facilitators like x402-sovereign handling payment verification and settlement without requiring API keys.