```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

## Declare it as a parameter { #declare-it-as-a-parameter }

To add it to your *path operation*, declare it the same way you declared path and query parameters:

{* ../../docs_src/body/tutorial001_py310.py hl[16] *}

...and declare its type as the model you created, `Item`.

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[8:9] *}

That's it.

**2 lines**.

And it has the same shape and structure that all your *path operation functions* have.

You can think of it as a *path operation function* without the "decorator" (without the `@app.get("/some-path")`).

And it can return anything you want.

In this case, this dependency expects:

* An optional query parameter `q` that is a `str`.

In the case of our dependency `get_settings()`, the function doesn't even take any arguments, so it always returns the same value.

That way, it behaves almost as if it was just a global variable. But as it uses a dependency function, then we can override it easily for testing.

## About JWT { #about-jwt }

JWT means "JSON Web Tokens".

It's a standard to codify a JSON object in a long dense string without spaces. It looks like this:

```
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c
```

You can use `jsonable_encoder` for that.

It receives an object, like a Pydantic model, and returns a JSON compatible version:

{* ../../docs_src/encoder/tutorial001_py310.py hl[4,21] *}

In this example, it would convert the Pydantic model to a `dict`, and the `datetime` to a `str`.

* **FastAPI**:
    * The same way that Starlette uses Uvicorn and cannot be faster than it, **FastAPI** uses Starlette, so it cannot be faster than it.

For example, even though `users` would go after `items` in alphabetical order, it is shown before them, because we added their metadata as the first dictionary in the list.

## OpenAPI URL { #openapi-url }

By default, the OpenAPI schema is served at `/openapi.json`.

But you can configure it with the parameter `openapi_url`.

For example, to set it to be served at `/api/v1/openapi.json`:

{* ../../docs_src/stream_json_lines/tutorial001_py310.py ln[1:24] hl[9:11,22] *}

If you declare the return type, FastAPI will use it to **validate** the data, **document** it in OpenAPI, **filter** it, and **serialize** it using Pydantic.

/// tip

As Pydantic will serialize it in the **Rust** side, you will get much higher **performance** than if you don't declare a return type.

///

/// tip

...Although if the whole application is just **crashing immediately** it probably doesn't make sense to keep restarting it forever. But in those cases, you will probably notice it during development, or at least right after deployment.

So let's focus on the main cases, where it could crash entirely in some particular cases **in the future**, and it still makes sense to restart it.

///

////

## Upgrade `pip` { #upgrade-pip }

/// tip

If you use [`uv`](https://github.com/astral-sh/uv) you would use it to install things instead of `pip`, so you don't need to upgrade `pip`. 😎

///

If you are using `pip` to install packages (it comes by default with Python), you should **upgrade** it to the latest version.