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15 FastAPI Best Practices For Production
Excerpt
00:00 Introduction to FastAPI Best Practices 00:22 Avoid Async for Blocking Operations 01:24 Use Async Friendly Code 01:46 Avoid Heavy Computation in Endpoints 02:51 FastAPI Dependencies Rules 03:11 Don't Make Users Wait (Background Tasks) 04:00 Don't Expose Swagger/ReDoc in Production 04:22 Create Custom Pydantic Base Model 05:00 Don't Manually Construct Response Models 05:23 Validate with Pydantic, Not Your Code 06:01 Use Dependencies for DB-Based Validation 06:33 Avoid New DB Connections in Every Endpoint 07:27 Use Lifespan Events for Resource Management 08:02 Don't Hardcode Secrets 09:29 Use Structured Logging 11:24 Best Practices for Deploying FastAPI You'll learn how to: ✅ Avoid common async mistakes ✅ Optimize database connections ✅ Handle background tasks the right way ✅ Secure your API in production ✅ Improve performance with structured logging ✅ Deploy FastAPI using Uvicorn + Gunicorn + uvloop ... FastAPI is designed to recognize that {ts:74} you're performing blocking operations within these def endpoints and will intelligently run them in separate threads. This way, {ts:81} your FastAPI application remains responsive. Number two, use async friendly code. To get the most performance out {ts:88} of your FastAPI application, use non-blocking libraries as much as possible so you can declare your endpoints as {ts:94} async endpoints. Use asyncio.sleep instead of time.sleep httpx.AsyncClient instead of the requests module {ts:102} and motor instead of pymongo. I hope you get the idea. Number three, don't do heavy computation {ts:108} in FastAPI endpoints, or you'll block your server. FastAPI is built for I/O-bound workloads. {ts:114} So, avoid processing images or videos or running heavy machine learning models {ts:118} directly in your endpoints. The reason is that your application will be unresponsive for as long {ts:123} as the computation runs. What should you do instead? … {ts:220} limitations: don't use BackgroundTasks for anything requiring guaranteed delivery, retries, or tasks that run for a long duration. {ts:228} For those more robust needs, a dedicated message queue and worker system (like Celery) is still the superior {ts:234} choice. Remember, if your FastAPI process crashes before a background task completes, that task will fail. {ts:240} Number six, don't expose Fastapi Swagger or ReDoc in production unless your API is public-facing. FastAPI automatically generates {ts:248} these docs, which is great during development. But in production, they can reveal {ts:252} endpoints that might still be incomplete or lack proper security. … Don't scatter validation across your route functions with if statements and manual {ts:333} checks. It might seem easier at first, but it quickly turns into a mess. You lose consistent error {ts:339} responses, and clients get cryptic 400s with no clue why their request failed. You end up repeating the
Related Pain Points
BackgroundTasks Lack Reliability for Critical Work
6FastAPI's BackgroundTasks cannot guarantee delivery or retries, and if the FastAPI process crashes before a task completes, that task will be lost. This is unsuitable for work requiring guaranteed execution.
Async/await complexity and blocking event loop anti-patterns
6Developers frequently block event loops with sync I/O calls (e.g., using `requests` instead of `aiohttp`), throttling async performance. Missing `await` keywords cause runtime exceptions rather than compile-time hints.