x402

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

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.

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
On 14 July 2026 the x402 Foundation launched operationally under the Linux Foundation with 40 member organizations, moving stewardship of the spec beyond Coinbase alone. Transaction-volume figures are deliberately not quoted here: no primary source publishes one, so the site's single attributed count (agenteconomy.to, reported not audited) lives at /protocols/x402.
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

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