* If you are comparing Starlette, compare it against Sanic, Flask, Django, etc. Web frameworks (or microframeworks).
* **FastAPI**:
    * The same way that Starlette uses Uvicorn and cannot be faster than it, **FastAPI** uses Starlette, so it cannot be faster than it.

{!../../../docs_src/path_params/tutorial003.py!}
```

Otherwise, the path for `/users/{user_id}` would match also for `/users/me`, "thinking" that it's receiving a parameter `user_id` with a value of `"me"`.

Similarly, you cannot redefine a path operation:

```Python hl_lines="6  11"
{!../../../docs_src/path_params/tutorial003b.py!}
```

The first one will always be used since the path matches first.

## Predefined values

These status codes have a name associated to recognize them, but the important part is the number.

In short:

* `100` and above are for "Information". You rarely use them directly.  Responses with these status codes cannot have a body.
* **`200`** and above are for "Successful" responses. These are the ones you would use the most.
    * `200` is the default status code, which means everything was "OK".

## Using the `jsonable_encoder` in a `Response`

Because **FastAPI** doesn't do any change to a `Response` you return, you have to make sure it's contents are ready for it.

For example, you cannot put a Pydantic model in a `JSONResponse` without first converting it to a `dict` with all the data types (like `datetime`, `UUID`, etc) converted to JSON-compatible types.

* `allow_credentials` - Indicate that cookies should be supported for cross-origin requests. Defaults to `False`. Also, `allow_origins` cannot be set to `['*']` for credentials to be allowed, origins must be specified.
* `expose_headers` - Indicate any response headers that should be made accessible to the browser. Defaults to `[]`.