Glossary

Authorization: A signed ERC-3009 TransferWithAuthorization message that permits a token transfer within a time window.

Backend: Your server or API that requires payment before servicing a request.

ERC-3009: Token standard for gasless transfer authorizations.

Exact scheme: x402 payment scheme where each request must match an exact amount.

Facilitator: Hosted service that verifies payment payloads and submits settlement transactions.

Payment requirements: The required scheme, network, asset, recipient, amount, and timeout for a valid payment.

RPC URL: A blockchain node endpoint used to read state and submit transactions.

Settlement: The on-chain transfer executed by the facilitator after verification.

x402: Payment protocol for paid API access using ERC-20 token transfers.