# x402

> A protocol that uses the HTTP 402 'Payment Required' status so an agent can pay for a resource inline with a stablecoin micropayment.

_The Agentic Web Lexicon · /glossary/x402 · [JSON](/api/glossary/x402) · [all The Agentic Web Lexicon](/glossary)_

- **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-commerce, agent-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-commerce, agent-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