# 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.

_The Agent Protocol Atlas · /protocols/x402 · [JSON](/api/protocols/x402) · [all The Agent Protocol Atlas](/protocols)_

- **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 Payments, x402 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
- **maturity_tag:** production-ready
- **current_spec_version:** — (verify-against-primary-at-build)
- **spec_date:** — (verify-against-primary-at-build)
- **launch_date:** 2025
- **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)
- **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