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.

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.

name
x402
full_name
HTTP 402 Payments
layer
payments
creator
Coinbase + web3 ecosystem partners
status
live · volume reported, not audited
source
Spec: https://x402.org (Coinbase, 2025). Volume: agenteconomy.to, a community on-chain dashboard, as of 2026-07-30 — reported, not audited, and uncorroborated by a second tracker. No primary source publishes a comparable figure; see adoption_metric for the competing counts.
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 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
2026-07-30
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
159,604,144 cumulative settled transactions and $41.1M stablecoin volume, across the 7 chains and 18 facilitators agenteconomy.to tracks (as of 2026-07-30) attributed-not-audited ↗ https://agenteconomy.to (community on-chain dashboard; queries at https://github.com/realdora/agenteconomy). Competing counts: https://www.coinbase.com/developer-platform/discover/launches/x402 (Coinbase ecosystem, 165M+, Apr 2026) and https://web3trackers.com/x402-dashboard (120M+, 2026-04-14).
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

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