FastAPI Patterns
Production-oriented patterns for FastAPI services.
When to Use
- Building or reviewing a FastAPI app.
- Splitting routers, schemas, dependencies, and database access.
- Writing async endpoints that call a database or external service.
- Adding authentication, authorization, OpenAPI docs, tests, or deployment settings.
- Checking a FastAPI PR for copy-pasteable examples and production risks.
How It Works
Treat the FastAPI app as a thin HTTP layer over explicit dependencies and service code:
main.pyowns app construction, middleware, exception handlers, and router registration.schemas/owns Pydantic request and response models.dependencies.pyowns database, auth, pagination, and request-scoped dependencies.services/orcrud/owns business and persistence operations.tests/overrides dependencies instead of opening production resources.
Prefer small routers and explicit response_model declarations. Keep raw ORM objects, secrets, and framework globals out of response schemas.
Project Layout
app/
|-- main.py
|-- config.py
|-- dependencies.py
|-- exceptions.py
|-- api/
| `-- routes/
| |-- users.py
| `--…
