Event Sourcing over CRUD for Financial Transaction Audit Trails

The team decided to move from standard CRUD in PostgreSQL to Event Sourcing for financial transaction audit trails. The problem with CRUD is that updates overwrite previous states, losing compliance history (e.g., who changed transaction #8821 status from pending to approved). Database triggers were considered but rejected because they lose business context - triggers see row changes but not why the change happened or user intent. Event Sourcing stores immutable domain events (TransactionCreated, TransactionApproved, StatusUpdated) via Kafka, with materialized views in Postgres for fast reads. Martin Fowler Event Sourcing Pattern article is the reference architecture. Implementation: event producers in src/services/transactionService.ts, consumer/store logic in src/events/eventStore.ts.