Auf die gleiche Weise können Sie optionale Query-Parameter deklarieren, indem Sie deren Defaultwert auf `None` setzen:

=== "Python 3.10+"

    ```Python hl_lines="7"
    {!> ../../../docs_src/query_params/tutorial002_py310.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="9"
    {!> ../../../docs_src/query_params/tutorial002.py!}
    ```

```Python hl_lines="1  18"
{!../../../docs_src/response_directly/tutorial002.py!}
```

### `HTMLResponse`

Takes some text or bytes and returns an HTML response, as you read above.

### `PlainTextResponse`

Takes some text or bytes and returns an plain text response.

```Python hl_lines="2  7  9"
{!../../../docs_src/custom_response/tutorial005.py!}
```

=== "Python 3.10+ Pydantic v2"

    ```Python hl_lines="13-24"
    {!> ../../../docs_src/schema_extra_example/tutorial001_py310.py!}
    ```

=== "Python 3.10+ Pydantic v1"

    ```Python hl_lines="13-23"
    {!> ../../../docs_src/schema_extra_example/tutorial001_py310_pv1.py!}
    ```

=== "Python 3.8+ Pydantic v2"

    ```Python hl_lines="15-26"

=== "Python 3.10+ Pydantic v2"

    ```Python hl_lines="13-24"
    {!> ../../../docs_src/schema_extra_example/tutorial001_py310.py!}
    ```

=== "Python 3.10+ Pydantic v1"

    ```Python hl_lines="13-23"
    {!> ../../../docs_src/schema_extra_example/tutorial001_py310_pv1.py!}
    ```

=== "Python 3.8+ Pydantic v2"

    ```Python hl_lines="15-26"

=== "Python 3.10+"

    ```Python hl_lines="9"
    {!> ../../../docs_src/dependencies/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="11"
    {!> ../../../docs_src/dependencies/tutorial001_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="12"
    {!> ../../../docs_src/dependencies/tutorial001_an.py!}
    ```

=== "Python 3.10+"

    ```Python hl_lines="28-33"
    {!> ../../../docs_src/body_updates/tutorial001_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="30-35"
    {!> ../../../docs_src/body_updates/tutorial001_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="30-35"
    {!> ../../../docs_src/body_updates/tutorial001.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="4  8  12"
    {!> ../../../docs_src/security/tutorial006_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="2  7  11"
    {!> ../../../docs_src/security/tutorial006_an.py!}
    ```

=== "Python 3.8+ non-Annotated"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="2  6  10"

```

como em:

=== "Python 3.10+"

    ```Python hl_lines="15"
    {!> ../../../docs_src/body_multiple_params/tutorial005_py310.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="17"
    {!> ../../../docs_src/body_multiple_params/tutorial005.py!}
    ```

Neste caso o **FastAPI** esperará um corpo como:

```JSON hl_lines="2"
{
    "item": {
        "name": "Foo",

* `limit=10`: ↩️ 👈 🔢 💲

## 📦 🔢

🎏 🌌, 👆 💪 📣 📦 🔢 🔢, ⚒ 👫 🔢 `None`:

=== "🐍 3️⃣.6️⃣ & 🔛"

    ```Python hl_lines="9"
    {!> ../../../docs_src/query_params/tutorial002.py!}
    ```

=== "🐍 3️⃣.1️⃣0️⃣ & 🔛"

    ```Python hl_lines="7"
    {!> ../../../docs_src/query_params/tutorial002_py310.py!}
    ```

👉 💼, 🔢 🔢 `q` 🔜 📦, & 🔜 `None` 🔢.

!!! check

=== "Python 3.10+"

    ```Python hl_lines="12"
    {!> ../../../docs_src/body_nested_models/tutorial002_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="14"
    {!> ../../../docs_src/body_nested_models/tutorial002_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="14"
    {!> ../../../docs_src/body_nested_models/tutorial002.py!}
    ```