FastAPI Async and Task Integration

When to use

Invoke when a scaffolded FastAPI service must enqueue background work, publish domain events, or consume from a broker (Celery/RQ/arq on Redis, or Kafka), and the integration needs correct delivery semantics, idempotency, retry/DLQ, and an outbox so a database commit and an event publish cannot diverge.

Do not use for: the service shell, settings, or error tiers (use fastapi-service-scaffold), auth or OWASP review (use fastapi-auth-and-security-review), OpenTelemetry/metrics/SLO wiring (use fastapi-observability-readiness), or pool-sizing/circuit-breaker/load-test gating (use fastapi-performance-and-resilience).

Inputs

Required:

• A service with the fastapi-service-scaffold baseline (DI providers, validated settings, logging, ASGI-lifespan shutdown present).
• backend-architecture.md declaring the broker, the event/message contracts, and the delivery-semantics and retry strategy — or explicit confirmation a needed decision is intentionally deferred.

Optional: