Event-Driven Data Systems

Workflow

1. Define source of truth and stable identifiers for every entity.
2. Define delivery semantics and duplicate/retry/out-of-order meaning.
3. Make consumers idempotent with durable keys/constraints.
4. Separate domain state from provider payloads and retain enough event metadata for replay/audit.
5. Move retriable/slow work off synchronous request paths.
6. Define DLQ/error visibility and reconciliation for missed events.
7. Test duplicates, ordering, partial failures and replay.

Conditional references

• Delivery/retries/reconciliation → references/delivery-semantics.md.
• PostgreSQL idempotency → references/postgres-idempotency.md.

Asset

Use assets/event-contract.md to document events.