Payment Checkout & Ledger Service  ·  View 10 of 24  ·  Data

Data Flow — One Payment, End to End

Where the card number stops, where the money becomes a number, and where that number is proved.

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Capture Intent request + idempotency key Card details CDE only Normalise Network token no PAN onward Intent record merchant shard Attempt record one per provider call Emit Payment event ordered per intent Raw provider payload stored before parsed Post Posting rule vN Ledger transaction sums to zero 8 entries minor units Reconcile Settlement line provider truth Match or break Break account aged 48 h Serve Balance projection rebuildable Statement Trial balance daily tokenise natural key project Data Flow — One Payment, End to End Interface / broker Security / platform Data store Queue / topic Application we own External / third party Decision point Risk / gap synchronous event / async batch The primary account number stops at Capture. Everything downstream carries a token, the ledger carries integer minor units only, and an unmatched line becomes a correcting transaction rather than an edit. v 1.0 · owner Payments Platform Architecture · date 2026-10

Decisions

  • The primary account number stops at Capture. Everything downstream carries a network or vault token (ADR-11).
  • Ledger amounts are integer minor units with an explicit currency. Floating point is excluded by the data model, not by convention (ADR-02).
  • The raw provider payload is stored before it is parsed. A payload that cannot be parsed is still evidence (ADR-05).

Numbers

  • ~8 ledger entries per payment → ~96 M entries/day, ~35 bn/year, ~12 TB/year before compression.
  • A settlement line is the provider's truth; an unmatched line becomes a correcting transaction, never an edit.
  • Stated assumptions, all of them.

Risks

  • The 8-entries-per-payment figure drives the whole long-run storage model. If marketplace splits land (Phase 3) it roughly doubles, and the partitioning question (ADR-08) has to be re-opened.
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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 records10-payment-data-flow