!!! tip
    The "MINOR" is the number in the middle, for example, in `0.2.3`, the MINOR version is `2`.

## Upgrading the FastAPI versions

You should add tests for your app.

With **FastAPI** it's very easy (thanks to Starlette), check the docs: [Testing](../tutorial/testing.md){.internal-link target=_blank}

```Python hl_lines="1  7-12  19-20"
{!../../../docs_src/dataclasses/tutorial001.py!}
```

This is still supported thanks to **Pydantic**, as it has <a href="https://docs.pydantic.dev/latest/concepts/dataclasses/#use-of-stdlib-dataclasses-with-basemodel" class="external-link" target="_blank">internal support for `dataclasses`</a>.

# Testing

Thanks to <a href="https://www.starlette.io/testclient/" class="external-link" target="_blank">Starlette</a>, testing **FastAPI** applications is easy and enjoyable.

It is based on <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a>, which in turn is designed based on Requests, so it's very familiar and intuitive.

## Pydantic

All the data validation is performed under the hood by <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a>, so you get all the benefits from it. And you know you are in good hands.

You can use the same type declarations with `str`, `float`, `bool` and many other complex data types.

Several of these are explored in the next chapters of the tutorial.

## Order matters

name: Privileged
description: You are @tiangolo or he asked you directly to create an issue here. If not, check the other options. 👇
body:
  - type: markdown
    attributes:
      value: |
        Thanks for your interest in FastAPI! 🚀

    * [Dependencies - First Steps - Share `Annotated` dependencies](https://fastapi.tiangolo.com/tutorial/dependencies/#share-annotated-dependencies)

Special thanks to [@nzig](https://github.com/nzig) for the core implementation and to [@adriangb](https://github.com/adriangb) for the inspiration and idea with [Xpresso](https://github.com/adriangb/xpresso)! 🚀

### Features

It's better to discuss privately and try to find a solution first, to limit the potential impact as much as possible.

---

Thanks for your help!

## Sponsor the author

You can also financially support the author (me) through <a href="https://github.com/sponsors/tiangolo" class="external-link" target="_blank">GitHub sponsors</a>.

There you could buy me a coffee ☕️ to say thanks. 😄

And you can also become a Silver or Gold sponsor for FastAPI. 🏅🎉

## Sponsor the tools that power FastAPI

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Just Modern Python

It's all based on standard **Python type** declarations (thanks to Pydantic). No new syntax to learn. Just standard modern Python.

# Body - Nested Models

With **FastAPI**, you can define, validate, document, and use arbitrarily deeply nested models (thanks to Pydantic).

## List fields

You can define an attribute to be a subtype. For example, a Python `list`:

=== "Python 3.10+"

    ```Python hl_lines="12"
    {!> ../../../docs_src/body_nested_models/tutorial001_py310.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="14"