Facilitator — x402 settlement intermediary
A service that brokers x402 settlement validation and execution. Submits the client's payment payload on-chain and returns settlement status to the resource server.
Definition
In a pure peer-to-peer x402 configuration, the resource server has to confirm on-chain state itself, which is operationally heavy. The facilitator role factors that out, consolidating validation, submission, and confirmation in one place.
Coinbase Developer Platform hosts a facilitator that supports Base, Polygon, Arbitrum, World, and Solana, with a free tier of 1,000 transactions per month.
Facilitators hold no client secrets — this is an intermediary for availability, not confidentiality. The payment signature is created client-side; the facilitator only submits and verifies. Multiple facilitators can be selected.
Lemma Oracle implementation
Lemma's Trust402 works transparently with existing facilitators. Splitting the X-PAYMENT header (x402 standard) from the X-PROOF header (Trust402 extension) means facilitators that don't understand the proof header still settle payment correctly.
For workflows where verifiability is mandatory (financial services, public procurement), a Trust402-aware facilitator validates X-PROOF via ZK alongside payment validation, only finalizing when both succeed.
Gas costs for submitting the EIP-3009 signature on-chain are fronted by the facilitator and recovered later. The client is fully insulated from gas management.