facilitator

The x402 specification describes the facilitator as an optional service that simplifies verifying and settling payments between buyers and sellers. It verifies payment payloads submitted by clients and executes settlement of validated payments on-chain, so a seller needs no blockchain connectivity of its own. The protocol's documentation states that a facilitator does not hold funds and does not act as a custodian: it verifies and executes transactions from signed payloads the client provides.

A seller's endpoint answers an unpaid request with HTTP 402 and a machine-readable quote — the accepts array — naming the price, the receiving address (payTo), the network and the payment scheme. The client signs an authorization for that quote; under the exact scheme on EVM networks that signature is an EIP-3009 transferWithAuthorization. The seller passes the signed payload to the facilitator's /verify operation, fulfils the request, then calls /settle for the transfer to be submitted on-chain — the verify and settle pair.

Whichever facilitator a seller configures is where that seller's verification and settlement happen. A facilitator may also operate a discovery catalogue listing endpoints that settle through it. Separate facilitators keep separate catalogues, so the choice of facilitator decides both where payments settle and where an endpoint can be listed.