Event Sourcing over CRUD for Financial Transaction Audit Trails

The team decided to replace standard CRUD in PostgreSQL with Event Sourcing for financial transaction audit trails. The transition was driven by compliance requirements for full history tracking (e.g., transaction #8821 status changes). Database triggers were considered but rejected because they lose business context — they capture row-level changes without intent. Event Sourcing stores immutable domain events (TransactionCreated, TransactionApproved, StatusUpdated) in Kafka, with a Postgres materialized view for fast frontend reads. Implementation: event producers in src/services/transactionService.ts, consumer/store logic in src/events/eventStore.ts. Reference: Martin Fowler's Event Sourcing Pattern article.