FastAPI

This is how I set up clean and maintainable FastAPI projects: DI, testing, validation, logging, deployment, auth, and more.

Tip

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What’s inside#

Sections are ordered from foundational to advanced:

1. Project Structure – directory layout, pyproject.toml with uv, app factory pattern
2. Configuration – pydantic-settings, nested settings with prefixes, environment-specific overrides
3. Dependency Injection – idiomatic DI with Depends, lifespan, app.state, and when to reach for dependency-injector
4. Validation & Serialization – Pydantic models, custom validators, Annotated field metadata
5. Error Handling – custom exceptions, problem-detail responses (RFC 9457), validation error reshaping
6. Testing – pytest + httpx.AsyncClient, dependency_overrides, fixtures
7. Logging – loguru setup, structured JSON output, streaming to CloudWatch
8. Auth – OAuth2 with JWT, security schemes via Depends, role-based access
9. Deployment – multi-stage Dockerfile, uvicorn production settings, health checks