Overview

Pydantic 2.5, released on January 20, 2024, introduces the Pipeline API for chaining validators and a strict JSON mode.

Main Features

Pipeline API

The new Pipeline API lets you chain validation and transformation steps declaratively.

python 
from pydantic import BaseModel
from pydantic.experimental.pipeline import validate_as

chain = (
    validate_as(str)
    .str_strip()
    .str_to_lower()
    .str_pattern(r'^[a-z]+$')
)
print(chain('  Hello  '))  # ValueError

Strict JSON mode

The strict mode in model_validate_json rejects implicit coercions, ensuring exact types.

python 
from pydantic import BaseModel

class User(BaseModel):
    name: str
    age: int

data = '{"name": "Alice", "age": 30}'
user = User.model_validate_json(data, strict=True)
print(user.age)  # 30

Sources