# 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).

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...

## Password hashing

"Hashing" means converting some content (a password in this case) into a sequence of bytes (just a string) that looks like gibberish.

Whenever you pass exactly the same content (exactly the same password) you get exactly the same gibberish.

## Vélemények

"_[...] 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._"

# Alternatives, inspiration et comparaisons

Ce qui a inspiré **FastAPI**, comment il se compare à d'autres solutions et ce qu'il en a appris.

## Intro

**FastAPI** n'existerait pas sans les précédentes contributions d'autres projets.

De nombreux outils ont été créés auparavant et ont contribué à inspirer sa création.

J'ai évité la création d'un nouveau framework pendant plusieurs années. J'ai d'abord essayé de combler toutes les

│   └── internal
│       ├── __init__.py
│       └── admin.py
```

!!! tip
    There are several `__init__.py` files: one in each directory or subdirectory.

    This is what allows importing code from one file into another.

    For example, in `app/main.py` you could have a line like:

    ```
    from app.routers import items
    ```

## Opiniones

"_[...] 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._"

- <a href="https://github.com/Kludex/python-multipart" target="_blank"><code>python-multipart</code></a> - আপনি যদি ফর্ম সহায়তা করতে চান তাহলে প্রয়োজন <abbr title="converting the string that comes from an HTTP request into Python data">"parsing"</abbr>, `request.form()` সহ।
- <a href="https://pythonhosted.org/itsdangerous/" target="_blank"><code>itsdangerous</code></a> - `SessionMiddleware` সহায়তার জন্য প্রয়োজন।

class APIKeyQuery(APIKeyBase):
    """
    API key authentication using a query parameter.

    This defines the name of the query parameter that should be provided in the request
    with the API key and integrates that into the OpenAPI documentation. It extracts
    the key value sent in the query parameter automatically and provides it as the
    dependency result. But it doesn't define how to send that API key to the client.

    ## Usage