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FastAPI framework, high performance, easy to learn, fast to code, ready for production
Retry any Python function with exponential backoff, jitter, and custom stop conditions — three decorator lines replace 30 lines of retry logic.
| Metric | fastapi | tenacity |
|---|---|---|
| Ecosystem | Python | Python |
| Difficulty | Beginner | Beginner |
| Weekly downloads | 0 | 5.0M↑ |
| Latest version | v0.135.2 | v8.5.0 |
| Recipes | 1 | 2↑ |
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Use FastAPI when building REST or GraphQL APIs in Python, especially when you need async support, automatic OpenAPI/Swagger docs, request validation, or are building microservices. It's the best choice for new Python API projects.
Any I/O that can fail transiently: HTTP calls, database queries, queue operations, cloud API calls, file system operations on network drives.
FastAPI is API-only — it has no templating, admin interface, or ORM. For full-stack web apps with server-rendered HTML, Django is better. For tiny internal tools, Flask's smaller learning curve might be preferable.
Don't retry non-idempotent operations (POST that creates resources) without careful thought. Don't retry errors that won't resolve with time (auth failures, 400 Bad Request).
fastapi
tenacity