Coinbase has unveiled x402, a new on-chain payment protocol designed to support Base Sepolia and Solana networks. This chain-agnostic protocol aims to simplify the integration of Web3 payments for Web2 developers. A demonstration project has been launched to illustrate the protocol's functionality, featuring server, client, and facilitator components. The x402 middleware facilitates seamless integration with existing systems, while the client component manages payment signing and verification. This initiative seeks to standardize on-chain payments and enhance developer adoption.