You integrate with USDT Pay by implementing the protocol over the t-0 network. Communication uses Connect RPC, so every method is available over gRPC and over HTTP/JSON with the same request and response types. Every request is signed (see Request Authentication).

Your role determines which services you call and which callbacks you implement:

  • Acquirer — call AcquirerService (get a quote, create a payment intent, confirm fiat receipt); implement AcquirerCallbackService (authorization and settlement events).
  • Issuer — call IssuerService (payment received, settlement sent, expiry); implement IssuerCallbackService (create payment instructions).
  • Liquidity Provider — call LpService (publish and withdraw quotes, fiat settlement sent); implement LpCallbackService (execute quote).

The service and message definitions are in the API Reference, generated from acquirer.proto, issuer.proto, lp.proto, and types.proto. Generate your client and server stubs from those definitions.

API endpoints

Sandbox and production endpoints are provided during onboarding.

Idempotency and reliability

Every state-changing method declares an idempotency level for safe retries and duplicate prevention. See Idempotency and Reliability for the contract your endpoints must uphold and the reconciliation timers t-0 applies.