Executive Summary

x402 (Coinbase) and h402 (BitGPT) are new payment protocols that work by implementing the long-ignored HTTP 402 Payment Required status code. Their shared insight is that payment can be treated as a standard HTTP concern, enabling the next generation of autonomous, metered, accurate commerce over the public Internet. 

When a user (or agent) requests a monetized online resource, the server, instead of immediately granting access or showing a typical paywall, can reply with this 402 code. This response includes a JSON descriptor detailing the acceptable cryptocurrencies (like specific stablecoins, which aim for price stability), t