Then I found that there was a standard to document APIs, using JSON (or YAML, an extension of JSON) called Swagger.

And there was a web user interface for Swagger APIs already created. So, being able to generate Swagger documentation for an API would allow using this web user interface automatically.

At some point, Swagger was given to the Linux Foundation, to be renamed OpenAPI.

        Doc(
            """
            OpenAPI-specific examples.

            It will be added to the generated OpenAPI (e.g. visible at `/docs`).

            Swagger UI (that provides the `/docs` interface) has better support for the
            OpenAPI-specific examples than the JSON Schema `examples`, that's the main
            use case for this.

            Read more about it in the

```Python hl_lines="1  7-13  19"
{!../../../docs_src/dataclasses/tutorial002.py!}
```

The dataclass will be automatically converted to a Pydantic dataclass.

This way, its schema will show up in the API docs user interface:

<img src="/img/tutorial/dataclasses/image01.png">

## Dataclasses in Nested Data Structures

You can also combine `dataclasses` with other type annotations to make nested data structures.

## 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.

<a href="https://typer.tiangolo.com" target="_blank"><img src="https://typer.tiangolo.com/img/logo-margin/logo-margin-vector.svg" style="width: 20%;"></a>

Se stai sviluppando un'app <abbr title="Command Line Interface (interfaccia della riga di comando)">CLI</abbr> da usare nel terminale invece che una web API, ti consigliamo <a href="https://typer.tiangolo.com/" class="external-link" target="_blank">**Typer**</a>.

## **Typer**，命令行中的 FastAPI

<a href="https://typer.tiangolo.com" target="_blank"><img src="https://typer.tiangolo.com/img/logo-margin/logo-margin-vector.svg" style="width: 20%;"></a>

如果你正在开发一个在终端中运行的<abbr title="Command Line Interface">命令行</abbr>应用而不是 web API，不妨试下 <a href="https://typer.tiangolo.com/" class="external-link" target="_blank">**Typer**</a>。

**Typer** 是 FastAPI 的小同胞。它想要成为**命令行中的 FastAPI**。 ⌨️ 🚀

## 依赖

Python 及更高版本

## Check it

Run the server and go to the docs: <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

You'll see the user interface like:

<img src="/img/tutorial/security/image07.png">

Authorize the application the same way as before.

Using the credentials:

Username: `johndoe`
Password: `secret`

!!! check

By default, **FastAPI** will create a `server` in the OpenAPI schema with the URL for the `root_path`.

But you can also provide other alternative `servers`, for example if you want *the same* docs UI to interact with a staging and production environments.

## **Typer**, CLI এর জন্য FastAPI

<a href="https://typer.tiangolo.com" target="_blank"><img src="https://typer.tiangolo.com/img/logo-margin/logo-margin-vector.svg" style="width: 20%;"></a>

আপনি যদি <abbr title="Command Line Interface">CLI</abbr> অ্যাপ বানাতে চান, যা কিনা ওয়েব API এর পরিবর্তে টার্মিনালে ব্যবহার হবে, তাহলে দেখুন<a href="https://typer.tiangolo.com/" class="external-link" target="_blank">**Typer**</a>.

---

## **Typer**, o FastAPI das interfaces de linhas de comando

<a href="https://typer.tiangolo.com" target="_blank"><img src="https://typer.tiangolo.com/img/logo-margin/logo-margin-vector.svg" style="width: 20%;"></a>