Overview

Pydantic 2.3, released on October 13, 2023, improves JSON schema generation and adds new validators.

Main Features

Improved JSON schema

JSON schema generation is more spec-compliant and better supports Union types and references.

python 
from pydantic import BaseModel

class Address(BaseModel):
    street: str
    city: str

class User(BaseModel):
    name: str
    address: Address

schema = User.model_json_schema()
print(schema)  # $defs with references

New validators

New field validators are available, including field_validator with wrap mode for full control.

python 
from pydantic import BaseModel, field_validator

class Product(BaseModel):
    name: str
    price: float

    @field_validator('price')
    @classmethod
    def check_price(cls, v: float) -> float:
        if v <= 0:
            raise ValueError('Price must be positive')
        return round(v, 2)

Sources