starlette

Starlette is refreshingly straightforward if you're comfortable with ASGI concepts. The core APIs are intuitive - Request and Response objects work exactly as you'd expect, routing is clear with decorator syntax, and middleware composition is simple. Error messages are generally helpful, pointing you to the right method or parameter when you mess up route definitions or request handling.

The documentation is well-organized and covers all the components thoroughly, but it's somewhat sparse on real-world examples. You'll find yourself reading through the API reference more than following tutorials. Common tasks like handling file uploads, WebSockets, and background tasks are documented but often require piecing together multiple docs pages. The TestClient makes testing dead simple though - it's one of the best parts of the framework.

Community support is decent but smaller than FastAPI (which builds on Starlette). GitHub issues get responses, but Stack Overflow coverage is thin. You'll often need to read the source code, which fortunately is clean and readable. Debugging is straightforward since there's minimal magic happening under the hood.

Starlette provides a clean, minimalist ASGI framework with security-conscious defaults. CSRF protection is built-in via SessionMiddleware, HTTPS redirect middleware is straightforward to enable, and the framework properly handles security headers when configured. The middleware stack architecture makes it easy to layer authentication and request validation consistently.

The exception handling is generally safe—internal errors don't leak stack traces to clients by default in production mode. However, you need to be deliberate about custom exception handlers to avoid accidentally exposing sensitive data. The validation story requires bringing your own library (Pydantic integration is common), which means input validation discipline falls on you.

Dependency footprint is intentionally minimal, reducing supply chain risk. The maintainers respond to security issues promptly—I've seen CVEs addressed within days. TLS configuration depends on your ASGI server (uvicorn/hypercorn), not Starlette itself, which keeps concerns separated but means you must configure that layer separately.

Starlette hits the sweet spot between being lightweight and feature-complete. The learning curve is surprisingly gentle - if you understand basic async Python and HTTP concepts, you'll be productive within hours. The documentation is well-structured with clear examples for routing, middleware, background tasks, and WebSocket handling. I particularly appreciate how straightforward the Request and Response objects are compared to some frameworks.

Error messages are generally helpful, especially around route definition mistakes and middleware ordering issues. The stack traces are clean without layers of framework abstraction obscuring your actual code. Debugging is straightforward since Starlette doesn't employ much magic - you can easily step through request handling to understand what's happening.

Community support is solid through GitHub issues, and common questions are well-documented. The TestClient makes testing intuitive and doesn't require learning complex mocking patterns. My only friction points were around dependency injection patterns (not built-in, need to roll your own) and some advanced middleware scenarios requiring deeper ASGI knowledge.