Types/strict types

Strict types enable you to prevent coercion from compatible types.

Strict types

Pydantic provides the following strict types:

• StrictBool
• StrictBytes
• StrictFloat
• StrictInt
• StrictStr

These types will only pass validation when the validated value is of the respective type or is a subtype of that type.

Constrained types

This behavior is also exposed via the strict field of the constrained types and can be combined with a multitude of complex validation rules. See the individual type signatures for supported arguments.

• conbytes()
• condate()
• condecimal()
• confloat()
• confrozenset()
• conint()
• conlist()
• conset()
• constr()

The following caveats apply:

• StrictBytes (and the strict option of conbytes()) will accept both bytes, and bytearray types.
• StrictInt (and the strict option of conint()) will not accept bool types, even though bool is a subclass of int in Python. Other subclasses will work.
• StrictFloat (and the strict option of confloat()) will not accept int.

Besides the above, you can also have a FiniteFloat type that will only accept finite values (i.e. not inf, -inf or nan).

from pydantic import BaseModel, FiniteFloat, StrictInt, ValidationError


class StrictIntModel(BaseModel):
    strict_int: StrictInt


class Model(BaseModel):
    finite: FiniteFloat


try:
    StrictIntModel(strict_int=3.14159)
except ValidationError as e:
    print(e)
    """
    1 validation error for StrictIntModel
    strict_int
      Input should be a valid integer [type=int_type, input_value=3.14159, input_type=float]
    """
m = Model(finite=1.0)
print(m)
#> finite=1.0