x402
Revives the dormant HTTP 402 status code so an agent can pay for a resource inline — request, get 402 with terms, pay in stablecoin, retry.
- name
- x402
- full_name
- HTTP 402 Payments
- layer
- payments
- creator
- Coinbase + web3 ecosystem partners
- status
- live (165M+ transactions by Apr 2026)
- source
- x402 facilitator / ecosystem reporting (x402.org), 2026. Volume figures are ecosystem-reported, not independently audited.
- year
- 2025
- one_liner
- Revives the dormant HTTP 402 status code so an agent can pay for a resource inline — request, get 402 with terms, pay in stablecoin, retry.
- spec_url
- https://x402.org
- snippet
HTTP/1.1 402 Payment Required { "accepts": [{ "scheme": "exact", "maxAmountRequired": "$0.01", "payTo": "0x..." }] }- abbreviation
- x402
- also_known_as
HTTP 402 Paymentsx402 protocol- canonical_spec_url
- https://x402.org
- entity_uri
- https://github.com/coinbase/x402
- taxonomy_layer
- payments
- sub_layer
- inline-http-payment
- protocol_type
- settlement
- central_problem
- Lets an agent pay for a web resource inline over plain HTTP — no account, API key, or monthly invoice — by reviving the HTTP 402 status code.
- maintainer
- Coinbase (coinbase/x402 on GitHub) + open facilitator ecosystem
- governance_body
- vendor (Coinbase) + open facilitator ecosystem
- license
- Apache-2.0 verify-against-primary-at-build ↗ https://github.com/coinbase/x402
- maturity_tag
- production-ready
- current_spec_version
- — verify-against-primary-at-build ↗ https://x402.org
- spec_date
- — verify-against-primary-at-build ↗ https://github.com/coinbase/x402
- launch_date
- 2025 verify-against-primary-at-build ↗ https://x402.org
- last_verified
- 2026-06-15
- transport
- HTTP (402 status + payment headers); on-chain stablecoin settlement (Base, Solana)
- core_mechanism
- A client requests a resource; the server returns HTTP 402 with accepted payment terms; the client signs a token-transfer authorization and retries with a payment header; a facilitator confirms on-chain settlement and the server delivers the resource — one extra round trip, fractions of a cent.
- discovery_endpoint
- HTTP 402 response with an `accepts` payment-terms array (per-resource; no fixed path)
- settlement_type
- stablecoin (on-chain, e.g. Base / Solana)
- adoption_metric
- 165M+ transactions by ~69k agents (cumulative, by late April 2026) verify-against-primary-at-build ↗ https://www.coinbase.com/developer-platform/discover/launches/x402 (primary x402/Coinbase Agent.market report)
- notable_adopters
{"value":"Coinbase","source":"https://x402.org"}{"value":"Cloudflare (x402 Foundation participant)","source":"https://blockeden.xyz/blog/2026/03/05/x402-foundation-ai-payment-internet/"}- relationships
{"predicate":"extends","target":"ap2","note":"AP2 -extends-> x402 (research §2 seed triple): AP2 builds mandate-based settlement on top of the x402 inline-payment pattern. Edge stored on both records."}{"predicate":"verifies","target":"web-bot-auth","note":"Web Bot Auth can cryptographically verify the agent making a paid x402 request."}- ideal_use_case
- Metering API or content access by the call/byte for autonomous agents, with sub-cent payments and no account setup.
- when_to_use
- When agents must pay tiny amounts per request inline and you want stablecoin settlement without subscriptions or API keys.
- when_not_to_use
- When you need card/bank rails, human-in-the-loop mandates, or larger structured purchases (use AP2 or ACP/Agentic Commerce), or when you cannot accept on-chain settlement.
- code_example
- HTTP/1.1 402 Payment Required Content-Type: application/json { "accepts": [{ "scheme": "exact", "maxAmountRequired": "$0.01", "payTo": "0x...", "network": "base" }] }
- agent_readiness_link
- agent-readiness/x402
- layer_legacy
- payment