"""
    custom_encoder = custom_encoder or {}
    if custom_encoder:
        if type(obj) in custom_encoder:
            return custom_encoder[type(obj)](obj)
        else:
            for encoder_type, encoder_instance in custom_encoder.items():
                if isinstance(obj, encoder_type):
                    return encoder_instance(obj)
    if include is not None and not isinstance(include, (set, dict)):

**FastAPI** will make sure to read that data from the right place instead of JSON.

!!! note "Technical Details"
    Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded` when it doesn't include files.

    But when the form includes files, it is encoded as `multipart/form-data`. If you use `File`, **FastAPI** will know it has to get the files from the correct part of the body.

This is because by default, FastAPI will inspect every item inside and make sure it is serializable as JSON, using the same [JSON Compatible Encoder](../tutorial/encoder.md){.internal-link target=_blank} explained in the tutorial. This is what allows you to return **arbitrary objects**, for example database models.

                        "error": "Expecting property name enclosed in double quotes"
                    },
                }
            ]
        }
    ) | IsDict(
        # TODO: remove when deprecating Pydantic v1
        {
            "detail": [
                {
                    "loc": ["body", 1],
                    "msg": "Expecting property name enclosed in double quotes: line 1 column 2 (char 1)",

                        "error": "Expecting property name enclosed in double quotes"
                    },
                }
            ]
        }
    ) | IsDict(
        # TODO: remove when deprecating Pydantic v1
        {
            "detail": [
                {
                    "loc": ["body", 1],
                    "msg": "Expecting property name enclosed in double quotes: line 1 column 2 (char 1)",

    format: Optional[str] = None
    # Ref: JSON Schema Validation 2020-12: https://json-schema.org/draft/2020-12/json-schema-validation.html#name-a-vocabulary-for-the-conten
    # A Vocabulary for the Contents of String-Encoded Data
    contentEncoding: Optional[str] = None
    contentMediaType: Optional[str] = None
    contentSchema: Optional["SchemaOrBool"] = None

Với **FastAPI**, bạn có được tất cả những tính năng của **Starlette**:

* Hiệu năng thực sự ấn tượng. Nó là <a href="https://github.com/encode/starlette#performance" class="external-link" target="_blank">một trong nhưng framework Python nhanh nhất, khi so sánh với **NodeJS** và **Go**</a>.
* Hỗ trợ **WebSocket**.
* In-process background tasks.

* In code blocks within the Markdown document, translate comments (`# a comment`), but leave the rest unchanged.

* Do not change anything enclosed in "``" (inline code).

* In lines starting with `===` or `!!!`, translate only the ` "... Text ..."` part. Leave the rest unchanged.

    Hug inspired **FastAPI** to declare a `response` parameter in functions to set headers and cookies.

### <a href="https://github.com/encode/apistar" class="external-link" target="_blank">APIStar</a> (<= 0.5)

Right before deciding to build **FastAPI** I found **APIStar** server. It had almost everything I was looking for and had a great design.

    🤗 😮 🍕 APIStar, & 1️⃣ 🧰 👤 🔎 🏆 👍, 🌟 APIStar.

    🤗 ℹ 😍 **FastAPI** ⚙️ 🐍 🆎 🔑 📣 🔢, & 🏗 🔗 ⚖ 🛠️ 🔁.

    🤗 😮 **FastAPI** 📣 `response` 🔢 🔢 ⚒ 🎚 & 🍪.

### <a href="https://github.com/encode/apistar" class="external-link" target="_blank">APIStar</a> (&lt;= 0️⃣.5️⃣)

▶️️ ⏭ 🤔 🏗 **FastAPI** 👤 🔎 **APIStar** 💽. ⚫️ ✔️ 🌖 🌐 👤 👀 &amp; ✔️ 👑 🔧.