What if I have a fixed route and a dynamic route?

Order matters! If you have `@app.get("/users/me")` and `@app.get("/users/{user_id}")`, you MUST put `/users/me` first. Otherwise, the dynamic route will catch the request and assume `user_id` is the string 'me'.

Can query parameters be lists?

Yes. If you define `q: list[str] = Query(default=[])`, FastAPI will automatically parse URLs like `?q=apple&q=banana` into a proper Python list `['apple', 'banana']`.

Why use `Path()` if I already have `int`?

You only need `Path()` if you need extra validation (like greater-than rules) or if you want to add metadata (like a title or description) specifically for the Swagger UI documentation.

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Path & Query Parameters

Master URL routing. Learn how to extract Path variables, handle complex Query strings, make parameters optional, and secure your endpoints using the Path() and Query() constraint functions.

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