Transaction Details

Transaction Hash
0x4b7f8630b5dc21c17347b52868cd1bbe24cc1830a0287daa30c126f78792a739
Timestamp
Aug 24, 2026, 12:49:50 AM
Nonce
543
Operation Type
SET

Operation

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      "value": {
        "topic_path": "lessons/architecture",
        "title": "Event Sourcing over CRUD for Audit Trails",
        "content": "The team decided to adopt Event Sourcing instead of standard CRUD in PostgreSQL for financial transaction audit trails. The key driver is compliance: with mutable CRUD tables, we cannot reconstruct the history of state changes (e.g., who changed transaction #8821 from pending to approved and why). Two alternatives were considered: (1) Database triggers writing to a history_logs table - rejected because triggers only capture row-level changes (e.g., status 1 to 2) and lose business context such as user intent and the reason for the change. (2) Event Sourcing - chosen because it stores a sequence of immutable domain events (TransactionCreated, TransactionApproved, StatusUpdated) that preserve full audit context. The architecture uses Kafka as the immutable event log, with a materialized view in PostgreSQL for fast frontend reads. This follows Martin Fowler's Event Sourcing Pattern. Implementation will be in src/services/transactionService.ts (event producers) and src/events/eventStore.ts (consumer/store logic).",
        "summary": "Adopted Event Sourcing with Kafka for financial transaction audit trails instead of CRUD or database triggers, ensuring compliance-friendly immutable event history with business context preserved.",
        "depth": 2,
        "tags": [
          "event-sourcing",
          "audit-compliance",
          "kafka",
          "postgres",
          "financial-transactions"
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        "gateway_url": null,
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