needed by API systems is data "<abbr title="also called marshalling, conversion">serialization</abbr>" which is taking data from the code (Python) and converting it into something that can be sent through the network. For example, converting an object containing data from a database into a JSON object. Converting `datetime` objects into strings, etc.

Another big feature needed by APIs is data validation, making sure that the data is valid, given certain parameters. For example, that some...

# Python Types Intro

Python has support for optional "type hints" (also called "type annotations").

These **"type hints"** or annotations are a special syntax that allow declaring the <abbr title="for example: str, int, float, bool">type</abbr> of a variable.

By declaring types for your variables, editors and tools can give you better support.

* 🌐 Add Korean translation for Tutorial - Intro. PR [#2317](https://github.com/tiangolo/fastapi/pull/2317) by [@hard-coders](https://github.com/hard-coders).
* 🌐 Add Chinese translation for Tutorial - Bigger Applications - Multiple Files. PR [#2453](https://github.com/tiangolo/fastapi/pull/2453) by [@waynerv](https://github.com/waynerv).

  - author: Sebastián Ramírez (tiangolo)
    author_link: https://twitter.com/tiangolo
    link: https://www.youtube.com/watch?v=PnpTY1f4k2U
    title: '[VIRTUAL] Py.Amsterdam''s flying Software Circus: Intro to FastAPI'
  - author: Sebastián Ramírez (tiangolo)
    author_link: https://twitter.com/tiangolo
    link: https://www.youtube.com/watch?v=z9K5pwb0rt8
    title: 'PyConBY 2020: Serve ML models easily with FastAPI'

That way, you can edit the documentation/source files and see the changes live.

!!! tip
    Alternatively, you can perform the same steps that scripts does manually.

    Go into the language directory, for the main docs in English it's at `docs/en/`:

    ```console
    $ cd docs/en/
    ```

    Then run `mkdocs` in that directory:

    ```console

    So, with that type declaration, **FastAPI** gives you automatic request <abbr title="converting the string that comes from an HTTP request into Python data">"parsing"</abbr>.

## Data validation

* Intégration Python facile avec **Jupyter Kernels** pour le développement à distance ou intra-Docker avec des extensions comme Atom Hydrogen ou Visual Studio Code Jupyter.
* Frontend **Vue** :
    * Généré avec Vue CLI.
    * Gestion de l'**Authentification JWT**.
    * Page de connexion.

```Python hl_lines="20-37  39-40"
{!../../../docs_src/path_operation_advanced_configuration/tutorial006.py!}
```

👉 🖼, 👥 🚫 📣 🙆 Pydantic 🏷. 👐, 📨 💪 🚫 <abbr title="converted from some plain format, like bytes, into Python objects">🎻</abbr> 🎻, ⚫️ ✍ 🔗 `bytes`, &amp; 🔢 `magic_data_reader()` 🔜 🈚 🎻 ⚫️ 🌌.

👐, 👥 💪 📣 📈 🔗 📨 💪.

### 🛃 🗄 🎚 🆎

⚙️ 👉 🎏 🎱, 👆 💪 ⚙️ Pydantic 🏷 🔬 🎻 🔗 👈 ⤴️ 🔌 🛃 🗄 🔗 📄 *➡ 🛠️*.

```

</div>

That would work for most of the cases. 😎

You could use that command for example to start your **FastAPI** app in a container, in a server, etc.

## ASGI Servers

Let's go a little deeper into the details.

FastAPI uses a standard for building Python web frameworks and servers called <abbr title="Asynchronous Server Gateway Interface">ASGI</abbr>. FastAPI is an ASGI web framework.

## Opinie

"_[...] I'm using **FastAPI** a ton these days. [...] I'm actually planning to use it for all of my team's **ML services at Microsoft**. Some of them are getting integrated into the core **Windows** product and some **Office** products._"