A402 architecture
A layered settlement runtime.
A402 separates gateway, payment logic, execution, receipts, settlement, and session/channel state into independent layers. Each layer can evolve without breaking the others.
Gateway Layer
Service registryOffer indexPolicy engine
Payment Logic
Intent verifierAuthorizationNonce / replay
Execution
Provider runtimeResult hashingLatency capture
Receipts & Settlement
Signed receiptsAtomic settlementRefund logic
Sessions & Channels
Prepaid balancesLocked fundsFuture atomic channels
Lifecycle
End-to-end flow
Step 01
Request
Client targets a paid service offer.
Step 02
Challenge
Provider returns a signed challenge + request hash.
Step 03
Signed Intent
Client signs a ServiceIntent authorizing the spend.
Step 04
Execute
Provider runs the call once the intent is verified.
Step 05
Receipt
Provider issues a signed execution receipt with result hash.
Step 06
Settlement
Settlement is finalized atomically against the intent.
- Step 01RequestClient targets a paid service offer.
- Step 02ChallengeProvider returns a signed challenge + request hash.
- Step 03Signed IntentClient signs a ServiceIntent authorizing the spend.
- Step 04ExecuteProvider runs the call once the intent is verified.
- Step 05ReceiptProvider issues a signed execution receipt with result hash.
- Step 06SettlementSettlement is finalized atomically against the intent.