Who created x402?
x402 was designed and open-sourced by Coinbase in May 2025, with the first public spec and reference implementation published under coinbase/x402 on GitHub. Governance transitioned to the Linux Foundation-hosted x402 Foundation on 2 April 2026, launching with 22 founding participants: Adyen, Amazon Web Services, American Express, Ampersend.ai, Base, Circle, Cloudflare, Coinbase, Fiserv Merchant Solutions, Google, KakaoPay, Mastercard, Merit Systems, Microsoft, Polygon Labs, PPRO, Shopify, Sierra, Solana Foundation, Stripe, thirdweb, and Visa.