### 步骤 1：导入 `FastAPI`

```Python hl_lines="1"
{!../../../docs_src/first_steps/tutorial001.py!}
```

`FastAPI` 是一个为你的 API 提供了所有功能的 Python 类。

!!! note "技术细节"
    `FastAPI` 是直接从 `Starlette` 继承的类。

    你可以通过 `FastAPI` 使用所有的 Starlette 的功能。

### 步骤 2：创建一个 `FastAPI`「实例」

```Python hl_lines="3"
{!../../../docs_src/first_steps/tutorial001.py!}
```

这里的变量 `app` 会是 `FastAPI` 类的一个「实例」。

```Python hl_lines="7"
{!../../../docs_src/first_steps/tutorial003.py!}
```

!!! note
    Nếu bạn không biết sự khác nhau, kiểm tra [Async: *"Trong khi vội vàng?"*](../async.md#in-a-hurry){.internal-link target=_blank}.

### Bước 5: Nội dung trả về

```Python hl_lines="8"
{!../../../docs_src/first_steps/tutorial001.py!}
```

```Python hl_lines="7"
{!../../../docs_src/first_steps/tutorial003.py!}
```

!!! note
    Jeśli nie znasz różnicy, sprawdź [Async: *"In a hurry?"*](../async.md#in-a-hurry){.internal-link target=_blank}.

### Krok 5: zwróć zawartość

```Python hl_lines="8"
{!../../../docs_src/first_steps/tutorial001.py!}
```

```Python hl_lines="7"
{!../../../docs_src/first_steps/tutorial003.py!}
```

!!! note "Nota"
    Se você não sabe a diferença, verifique o [Async: *"Com pressa?"*](../async.md#com-pressa){.internal-link target=_blank}.

### Passo 5: retorne o conteúdo

```Python hl_lines="8"
{!../../../docs_src/first_steps/tutorial001.py!}
```

```Python hl_lines="7"
{!../../../docs_src/first_steps/tutorial001.py!}
```

이것은 파이썬 함수입니다.

URL "`/`"에 대한 `GET` 작동을 사용하는 요청을 받을 때마다 **FastAPI**에 의해 호출됩니다.

위의 예시에서 이 함수는 `async`(비동기) 함수입니다.

---

`async def`을 이용하는 대신 일반 함수로 정의할 수 있습니다:

```Python hl_lines="7"
{!../../../docs_src/first_steps/tutorial003.py!}
```

!!! note "참고"

```Python hl_lines="7"
{!../../../docs_src/first_steps/tutorial003.py!}
```

!!! note "Not"
    Eğer farkı bilmiyorsanız, [Async: *"Aceleniz mi var?"*](../async.md#in-a-hurry){.internal-link target=_blank} sayfasını kontrol edebilirsiniz.

### Adım 5: İçeriği Geri Döndürün

```Python hl_lines="8"
{!../../../docs_src/first_steps/tutorial001.py!}
```

```Python hl_lines="7"
{!../../../docs_src/first_steps/tutorial003.py!}
```

!!! note "Nota"
    Si no sabes la diferencia, revisa el [Async: *"¿Tienes prisa?"*](../async.md#tienes-prisa){.internal-link target=_blank}.

### Paso 5: devuelve el contenido

```Python hl_lines="8"
{!../../../docs_src/first_steps/tutorial001.py!}
```

```Python hl_lines="7"
{!../../../docs_src/first_steps/tutorial003.py!}
```

!!! note
    Si vous ne connaissez pas la différence, allez voir la section [Concurrence : *"Vous êtes pressés ?"*](../async.md#vous-etes-presses){.internal-link target=_blank}.

### Étape 5 : retourner le contenu

```Python hl_lines="8"
{!../../../docs_src/first_steps/tutorial001.py!}
```

You could also use it to generate code automatically, for clients that communicate with your API. For example, frontend, mobile or IoT applications.

## Recap, step by step

### Step 1: import `FastAPI`

```Python hl_lines="1"
{!../../../docs_src/first_steps/tutorial001.py!}
```

`FastAPI` is a Python class that provides all the functionality for your API.

!!! note "Technical Details"

---

`async def`の代わりに通常の関数として定義することもできます:

```Python hl_lines="7"
{!../../../docs_src/first_steps/tutorial003.py!}
```

!!! note "備考"
    違いが分からない場合は、[Async: *"急いでいますか？"*](../async.md#_1){.internal-link target=_blank}を確認してください。

### Step 5: コンテンツの返信

```Python hl_lines="8"
{!../../../docs_src/first_steps/tutorial001.py!}
```

`dict`、`list`、`str`、`int`などを返すことができます。