fastapi-async-patterns

Use async route handlers with await for all IO operations, database queries, and external API calls. FastAPI automatically runs async endpoints in a thread pool, allowing concurrent request handling without blocking.

Integrate async ORM libraries and async database drivers to perform non-blocking queries. Await each database operation inside async route handlers to maximize throughput and responsiveness across multiple concurrent requests.

Use FastAPI's background tasks or task scheduling to fire-and-forget operations that execute independently. This separates long-running workloads from HTTP response cycles, keeping endpoints responsive.

CPU-bound tasks block the event loop and require offloading to worker processes or thread pools. Async patterns excel with IO-bound work; for CPU-bound operations, use dedicated worker services or libraries designed for parallel processing.

Send parallel requests using load testing tools or async HTTP clients to verify endpoints handle concurrency correctly. Test that async patterns eliminate blocking and that responses remain fast under concurrent load.

Async patterns eliminate blocking on IO operations, allowing a single server to handle many more concurrent requests. This improves throughput and responsiveness without needing additional worker processes.