End-of-Day Reconciliation

Proving the internal ledger agrees with what the banks actually did — an automated diffing engine over external clearing files.

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Table of Contents

1. Why reconciliation exists
2. The reconciliation loop

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Why reconciliation exists

Recording a movement internally is only half of correctness; the ledger must also be proven to agree with what the banks actually did. Reconciliation is an automated diffing engine that compares the internal ledger against external clearing files (BAI2, ISO 20022 CAMT.053, or clearinghouse CSVs) on a recurring cycle.

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    classDef dataLayer   fill:#2d6a4f,stroke:#52b788,color:#ffffff
    classDef workflow    fill:#5c4a8a,stroke:#c77dff,color:#ffffff
    classDef integration fill:#e9c46a,stroke:#f4a261,color:#1a1a1a
    classDef human       fill:#e76f51,stroke:#bc4749,color:#ffffff

    Files["Clearing files\nBAI2 · CAMT.053 · CSV"]:::integration
    Ingest["Ingestion\nnormalize to staging"]:::workflow
    Match["Matching engine\ntrace no. · idempotency key · amount/date/account"]:::workflow
    Ledger["Internal ledger"]:::dataLayer
    Recon["RECONCILED / SETTLED"]:::dataLayer
    Queue["Exception queue\noperator review"]:::human

    Files --> Ingest --> Match
    Ledger --> Match
    Match -->|matched| Recon
    Match -->|break| Queue

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The reconciliation loop

1. Ingestion — parse each incoming settlement file into a normalized external-transaction staging table.
2. Matching engine — match external records against internal ledger_transactions on external reference / network trace number, idempotency_key, and an amount + timestamp-window + account constraint.
3. Break classification — every record resolves to one of three outcomes:

Outcome	Meaning	Action
Matched	internal and external agree	advance the movement to RECONCILED / SETTLED
Unmatched (internal only)	we show funds sent; the bank statement doesn’t	raise a delayed-settlement alert
Unmatched (external only)	a debit/credit at the bank with no internal record	emit an exception event to the operational exception queue

Reconciliation runs as a durable Temporal workflow (see Temporal) so a mid-run failure resumes without double-counting, and every break becomes a human task with a full audit trail (see Data).