Why use it
- Useful for retries, agent loops, and unreliable networks.
- Server and/or facilitator can deduplicate using the same payment payload field.
How it works
- Your server advertises payment-identifier support and whether an id is required.
- The client supplies an id on the payment payload; consumers that understand the extension can cache or reject duplicates.
Highlighting Request
Request
Wallet, agent, or app that selects an offer and signs payment.
GET
GET
Sells access and publishes payment requirements.
GET
Verifies signatures and submits chain transactions on behalf of merchants.
402
Your server advertises payment-identifier support and whether an id is required.
Wallet, agent, or app that selects an offer and signs payment.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
{ "x402Version": 2 }Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Sells access and publishes payment requirements.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Verifies signatures and submits chain transactions on behalf of merchants.
Pay and retry
Wallet, agent, or app that selects an offer and signs payment.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Sells access and publishes payment requirements.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Verifies signatures and submits chain transactions on behalf of merchants.
Verify
Wallet, agent, or app that selects an offer and signs payment.
Sells access and publishes payment requirements.
verify
verify
Verifies signatures and submits chain transactions on behalf of merchants.
verify
Settle
Wallet, agent, or app that selects an offer and signs payment.
Sells access and publishes payment requirements.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Verifies signatures and submits chain transactions on behalf of merchants.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
Response
Wallet, agent, or app that selects an offer and signs payment.
200
200
Sells access and publishes payment requirements.
200
Verifies signatures and submits chain transactions on behalf of merchants.
Learn more
For engineers
Extension key payment-identifier.
Server advertises in PaymentRequired extensions; both resource servers and facilitators may read PaymentPayload—dedupe can happen at either or both layers.
- info.required boolean and optional id length bounds (16–128 chars) per schema.
- Id acts as idempotency key for repeated submissions.
