x402 Facilitator: The Party That Verifies and Settles Payments

x402 Facilitator: The Party That Verifies and Settles Payments

An x402 facilitator is the party in the x402 protocol that does the on-chain work a seller would otherwise do itself: given a buyer's signed payment, it verifies the signature, screens the transaction for compliance, submits the settlement transaction on-chain and reports the outcome. The role is optional. A seller with its own settlement infrastructure can skip the facilitator and still speak x402.

How does a facilitator work?

Coinbase's documentation describes two steps. Verify validates signed payments and performs compliance screening (OFAC sanctions and know-your-transaction checks). Settle submits validated payments to the blockchain and reports outcomes. In version 2 of the specification a facilitator exposes three HTTP endpoints: POST /verify, POST /settle and GET /supported.

A typical flow: the buyer's client retries a request with a payment header; the seller forwards the payment to a facilitator's verify endpoint; if valid, the seller serves the resource and calls settle. On EVM chains, the exact scheme settles through EIP-3009 transferWithAuthorization, so the facilitator is mechanically the third party that submits the buyer's signed authorization on-chain.

What does Coinbase's facilitator support?

As documented on 2026-09-27, Coinbase's CDP facilitator supports:

• EVM networks (Base, Polygon, Arbitrum, World): the exact, upto and batch-settlement schemes.
• Solana: exact and upto.
• Fees: verification is free; the first 1,000 on-chain settlements each month are free, then $0.001 each.
• Screening: it declines sanctioned or high-risk addresses.

It is the dominant instance, but version 2 allows multiple facilitators, and any facilitator may implement discovery.

Why does the facilitator matter?

It removes blockchain plumbing from sellers, which lowers the cost of becoming a machine-payable API. It is also where compliance happens: a script and an AI agent leave identical on-chain records, so screening addresses is the practical control. And it is the hinge to discovery. When a facilitator settles a payment for an endpoint that advertised x402 Bazaar metadata, it can index the endpoint so buyers and agents can find it. Registration is therefore triggered by a completed settlement, not by deployment, so a correct endpoint that has never sold anything has never been listed by that mechanism.

What are its limits?

• Trust and concentration. The facilitator sees payments and can decline them. A dominant facilitator is a chokepoint; the protocol's allowance for multiple facilitators and self-settlement is the mitigation.
• Security. Research published in May 2026 describes duplicate-settlement races, allowance overdraft and denial of settlement as flaw classes, and gaps between synchronous HTTP and asynchronous settlement.
• Regulatory uncertainty. Whether a facilitator taking x402 payments is a money transmitter under state law is not settled by the sources we reviewed.
• Catalogs are partial. A single facilitator's index is not the market; see x402 Bazaar and agent-market resource discovery.

Related

• What is x402?, x402 facilitator, x402 Bazaar, machine-payable API, micropayment, agent-to-agent commerce
• Evidence and measurement: The x402 economy, September 2026, x402 Bazaar and agent-market resource discovery
• Sites: market.561.group, 561.group, engineering.561.group, operations.561.group, services.561.group