Найпростіший файл FastAPI може виглядати так:

{* ../../docs_src/first_steps/tutorial001.py *}

Скопіюйте це до файлу `main.py`.

Запустіть сервер:

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:single">main.py</u>
<font color="#3465A4">INFO    </font> Using path <font color="#3465A4">main.py</font>

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    CountDownLatch computeSignal = new CountDownLatch(1);
    // tells the main thread when computation is pending
    CountDownLatch secondSignal = new CountDownLatch(1);
    // tells the main thread when the second get has started
    CountDownLatch thirdSignal = new CountDownLatch(1);
    // tells the main thread when the third get has started
    CountDownLatch fourthSignal = new CountDownLatch(1);

Here is the reference for it and its parameters.

You can import it directly from `fastapi`:

```python
from fastapi import Depends
```

::: fastapi.Depends

## `Security()`

For many scenarios, you can handle security (authorization, authentication, etc.) with dependencies, using `Depends()`.

But when you want to also declare OAuth2 scopes, you can use `Security()` instead of `Depends()`.

## Chamar `uvicorn` { #call-uvicorn }

Em sua aplicação FastAPI, importe e execute `uvicorn` diretamente:

{* ../../docs_src/debugging/tutorial001_py39.py hl[1,15] *}

### Sobre `__name__ == "__main__"` { #about-name-main }

O objetivo principal de `__name__ == "__main__"` é ter algum código que seja executado quando seu arquivo for chamado com:

<div class="termy">

```console
$ python myapp.py
```

</div>

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 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
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 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

/*
 * Copyright 2012-2025 CodeLibs Project and the Others.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

/*
 * Copyright 2012-2025 CodeLibs Project and the Others.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,