Body

Declares a parameter to be extracted from the request's JSON body, allowing for metadata configuration, validation constraints, and OpenAPI documentation customization. It supports embedding parameters as keys within the JSON body and provides extensive options for data validation and schema generation.

def Body(
    default: Any = Undefined,
    default_factory: Callable[[], Any] | None = _Unset,
    embed: bool | None = null,
    media_type: str = application/json,
    alias: str | None = null,
    alias_priority: int | None = _Unset,
    validation_alias: str | AliasPath | AliasChoices | None = null,
    serialization_alias: str | None = null,
    title: str | None = null,
    description: str | None = null,
    gt: float | None = null,
    ge: float | None = null,
    lt: float | None = null,
    le: float | None = null,
    min_length: int | None = null,
    max_length: int | None = null,
    pattern: str | None = null,
    regex: str | None = null,
    discriminator: str | None = null,
    strict: bool | None = _Unset,
    multiple_of: float | None = _Unset,
    allow_inf_nan: bool | None = _Unset,
    max_digits: int | None = _Unset,
    decimal_places: int | None = _Unset,
    examples: list[Any] | None = null,
    example: Any | None = _Unset,
    openapi_examples: dict[str, Example] | None = null,
    deprecated: deprecated | str | bool | None = null,
    include_in_schema: bool = true,
    json_schema_extra: dict[str, Any] | None = null,
    extra: Any = null
) - > Any

Declares a parameter that should be extracted from the request body. Use this to configure validation, documentation, and metadata for JSON body fields in FastAPI path operations.

Parameters

Name	Type	Description
default	Any = Undefined	Default value if the parameter field is not set.
default_factory	`Callable[[], Any]	None` = _Unset
embed	`bool	None` = null
media_type	str = application/json	The media type of this parameter field used for OpenAPI documentation generation.
alias	`str	None` = null
alias_priority	`int	None` = _Unset
validation_alias	`str	AliasPath
serialization_alias	`str	None` = null
title	`str	None` = null
description	`str	None` = null
gt	`float	None` = null
ge	`float	None` = null
lt	`float	None` = null
le	`float	None` = null
min_length	`int	None` = null
max_length	`int	None` = null
pattern	`str	None` = null
regex	`str	None` = null
discriminator	`str	None` = null
strict	`bool	None` = _Unset
multiple_of	`float	None` = _Unset
allow_inf_nan	`bool	None` = _Unset
max_digits	`int	None` = _Unset
decimal_places	`int	None` = _Unset
examples	`list[Any]	None` = null
example	`Any	None` = _Unset
openapi_examples	`dict[str, Example]	None` = null
deprecated	`deprecated	str
include_in_schema	bool = true	Whether to include this parameter in the generated OpenAPI documentation.
json_schema_extra	`dict[str, Any]	None` = null
extra	Any = null	Deprecated keyword arguments for extra JSON Schema fields; use 'json_schema_extra' instead.

Returns

Type	Description
Any	A FastAPI parameter metadata object used by the dependency injection system to parse and validate the request body.