Type hints

Field() infers its conversion from the field's annotation. When the annotation is ambiguous, pass type_hint= explicitly.

Supported type_hint values

type_hint	Converted to	Example
any	str (raw value)	value: Any = Field(type_hint="any")
bool	bool	debug: bool = Field(type_hint="bool")
float	float	ratio: float = Field(type_hint="float")
int	int	count: int = Field(type_hint="int")
str	str	name: str = Field(type_hint="str")
list	list[str]	tags: list[str] = Field(type_hint="list")
json	Any (json.loads)	settings: dict = Field(type_hint="json")

Inference from annotations

When an annotation is one of the simple types above, type_hint can be omitted:

class MyConfig(EnvConfig):
    env_prefix: str = "MYAPP"

    # annotation → type_hint inferred automatically
    debug: bool = Field()
    port: int = Field(default=8080)
    timeout: float = Field(default=5.0)

Pass type_hint="list" for list[str] fields whose annotation is parametrised; pass type_hint="json" for dict[...] annotations that should be parsed via json.loads.

Custom types

For anything outside the built-in set — enums, Decimal, pathlib.Path, nested dataclasses — use convert_using.