It will perform the validation of the compound data, and will document it like that for the OpenAPI schema and automatic docs.

## Singular values in body { #singular-values-in-body }

The same way there is a `Query` and `Path` to define extra data for query and path parameters, **FastAPI** provides an equivalent `Body`.

///

## Without Pydantic { #without-pydantic }

* Data conversion
* Data validation
* Automatic documentation

## Special types and validation { #special-types-and-validation }

Apart from normal singular types like `str`, `int`, `float`, etc. you can use more complex singular types that inherit from `str`.

### `scope` { #scope }

The spec also says that the client can send another form field "`scope`".

The form field name is `scope` (in singular), but it is actually a long string with "scopes" separated by spaces.

Each "scope" is just a string (without spaces).

They are normally used to declare specific security permissions, for example:

///

### Step 5: return the content { #step-5-return-the-content }

{* ../../docs_src/first_steps/tutorial001.py hl[8] *}

You can return a `dict`, `list`, singular values as `str`, `int`, etc.

You can also return Pydantic models (you'll see more about that later).

`Optional[str]` の`Optional` はFastAPIでは使用されていません（FastAPIは`str`の部分のみ使用します）。しかし、`Optional[str]` はエディタがコードのエラーを見つけるのを助けてくれます。

///

## Pydanticを使わない方法

		if _, ok := ownFieldsMap[joinFieldName]; ok {
			if field.Name != relation.FieldSchema.Name {
				joinFieldName = inflection.Singular(field.Name) + relField.Name
			} else {
				joinFieldName += "Reference"
			}
		}

		if len(joinReferences) > idx {
			joinFieldName = cases.Title(language.Und, cases.NoLower).String(joinReferences[idx])

This isn't even Python, NestJS is a JavaScript (TypeScript) NodeJS framework inspired by Angular.

It achieves something somewhat similar to what can be done with Flask-apispec.

```

</div>

## WebSockets client { #websockets-client }

### In production { #in-production }

In your production system, you probably have a frontend created with a modern framework like React, Vue.js or Angular.

And to communicate using WebSockets with your backend you would probably use your frontend's utilities.

Or you might have a native mobile application that communicates with your WebSocket backend directly, in native code.