Payment Checkout & Ledger Service  ·  View 14 of 24  ·  Runtime

The Unknown Outcome

The flow that is not an error path: the provider does not answer, and nobody may guess.

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Buyer Intent service Provider adapter Acquirer Outcome poller Settlement matcher Ledger Merchant 1. confirm 2. authorize 3. auth request 4. no answer in 8 s 5. result=unknown 6. state := processing 7. processing, do not retry 8. re-taps: same key 9. same intent, no 2nd attempt 10. inquiry (if supported) 11. still unknown 12. T+1 file: ref present 13. resolve → authorized 14. post, event_id key 15. webhook: succeeded Critical Flow — The Unknown Outcome No second provider attempt is ever made after an unknown. The resolution ladder is inquiry, then the settlement file, and the file is the evidence. v 1.0 · owner Payments Platform Architecture · date 2026-10

The rule

  • No second provider attempt is ever made after an unknown result. A retry is the one action that can produce a double charge, and the double-charge budget is ≤ 1 per 1,000,000 attempts (ADR-04).
  • The resolution ladder is inquiry (where the provider supports it), then the settlement file. The file is the evidence.

Decisions

  • `processing` is a terminal-pending state that only an inbound signal or a reconciliation job may leave — never a client retry (ADR-04).
  • The buyer re-tapping is served by the edge idempotency key and produces no second attempt (ADR-03).
  • The settlement matcher is allowed to resolve payment state, which makes a batch job a writer to the payment path — accepted deliberately, with constraints, in ADR-12.

Risks

  • Resolution can take up to 24 hours. A merchant who ships on `processing` has taken a risk the platform has told them not to take, and some will.
  • Void-and-retry would resolve in seconds and depends on a provider honouring a void for a transaction it may not admit exists. The trade is Question 2 and the decision is ADR-04.
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Solution Architecture v1.0 · open source, self-hosted on Kubernetes across two in-country data centres · Payments Platform Architecture · 2026-10 · 24 views · 18 architecture decision records14-unknown-outcome-resolution