X402 and MPP are both designed to serve AI agents, facilitating automatic payments when AI agents purchase services online or call APIs. Previously, AI agents had to manually click to pay for paid APIs; Now, it can achieve fully automated, even hundreds or thousands of micro-payments (for example, charging $0.001 each time an API is called). Both use the HTTP 402 status code; Both support cryptocurrencies and fiat currencies (like credit cards); Both support on-chain settlement. If the fiat currency part goes through the traditional Stripe channel, it is not completely pure on-chain settlement. In summary, both X402 and MPP aim to solve the payment issues for AI agents. However, there are significant differences: X402 is primarily promoted by Coinbase, aiming for crypto-native free payments. The payment experience is more akin to "cash payments": When the AI agent requests a paid service, the server says "pay up," and the AI agent transfers from its on-chain wallet (like ERC20), attaches the transfer proof, and requests again, completing the transaction. Its advantage is that it is very open and free; anyone can participate without being tied to any company or chain, achieving truly crypto-native decentralization. Its drawback is that essentially, every request requires a payment, which can be a bit exhausting for the AI during high-frequency calls (it is currently being modified to a prepaid model to alleviate this). MPP is promoted by Stripe and Tempo, called the Machine Payment Protocol, aiming for a more optimized payment experience. The payment experience is more like "membership card/pre-authorization limit": ...