x402
A protocol that uses the HTTP 402 'Payment Required' status so an agent can pay for a resource inline with a stablecoin micropayment.
- term
- x402
- category
- commerce
- short_def
- A protocol that uses the HTTP 402 'Payment Required' status so an agent can pay for a resource inline with a stablecoin micropayment.
- long_def
- Launched by Coinbase in May 2025. The server answers an unpaid request with 402 and machine-readable payment terms (amount, asset, network, recipient); the agent pays in a stablecoin such as USDC and retries with cryptographic proof of payment. On 23 September 2025 Coinbase and Cloudflare announced the x402 Foundation to steward the standard.
- see_also
agentic-commerceagent-identity- etymology_origin
- Launched by Coinbase in May 2025; named after the long-dormant HTTP 402 'Payment Required' status code. Stewardship moved to the x402 Foundation (Coinbase + Cloudflare), announced 23 September 2025.
- related_to
agentic-commerceagent-identity- contrast_with
- Unlike AP2, which is the authorization layer (cryptographic payment mandates), x402 is the settlement layer that actually moves the stablecoin — AP2 extends x402 rather than replacing it.
- example
- As of March 2026, x402 had processed over 119 million transactions on Base and 35 million on Solana, with roughly $600 million in annualized volume and zero protocol fees.
- source
- https://www.coinbase.com/developer-platform/discover/launches/x402
- status
- active
- why_it_matters
- x402 is the leading HTTP-native rail for an agent to pay for content or tools inline, making pay-per-call and pay-per-crawl monetization possible without legacy billing.
- sameAs
https://en.wikipedia.org/wiki/X402- bridge_entity
- protocols/payments/x402
- last_verified
- 2026-06-15
- md_twin
- /glossary/x402.md