Quick Summary

May 2025

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. x402 is the original, minimal schema put out by Coinbase a couple months ago. h402 is a newer superset built by BitGPT that keeps the x402 format but add a richer, five-stage lifecycle and works with more blockchains.

When a user (or agent) requests a monetized online resource, the server, instead of immediately gr