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README
Pydantic Validation
Data validation using Python type hints.
Fast and extensible, Pydantic plays nicely with your linters/IDE/brain.
Define how data should be in pure, canonical Python 1+; validate it with Pydantic.
Pydantic Logfire :fire:
Logfire is an observability and evaluation platform for AI applications and agents. Debug and trace agent execution, evaluate AI outputs, and manage model interactions through an integrated AI gateway.
Explore Logfire’s AI observability and evaluation platform.
Pydantic V1.10 vs. V2
Pydantic V2 is a ground-up rewrite that offers many new features, performance improvements, and some breaking changes compared to Pydantic V1.
If you're using Pydantic V1 you may want to look at the
pydantic V1.10 Documentation or,
1.10.X-fixes git branch. Pydantic V2 also ships with the latest version of Pydantic V1 built in so that you can incrementally upgrade your code base and projects: from pydantic import v1 as pydantic_v1.
Help
See documentation for more details.
Installation
Install using pip install -U pydantic or conda install pydantic -c conda-forge.
For more installation options to make Pydantic even faster,
see the Install section in the documentation.
A Simple Example
python
from datetime import datetime
from typing import Optional
from pydantic import BaseModel
class User(BaseModel):
id: int
name: str = 'John Doe'
signup_ts: Optional[datetime] = None
friends: list[int] = []
external_data = {'id': '123', 'signup_ts': '2017-06-01 12:22', 'friends': [1, '2', b'3']}
user = User(external_data)
print(user)
User id=123 name='John Doe' signup_ts=datetime.datetime(2017, 6, 1, 12, 22) friends=[1, 2, 3]
print(user.id)
123
Contributing
For guidance on setting up a development environment and how to make a
contribution to Pydantic, see
Contributing to Pydantic.
Reporting a Security Vulnerability
See our security policy.News & coverage (16)
Hacker NewsMCP Run Python▲ 173 · 66 comments · 2025-04-15Hacker NewsJSON extra uses orjson instead of ujson (2019)▲ 69 · 16 comments · 2024-06-05Hacker NewsAgent Framework / shim to use Pydantic with LLMs▲ 7 · 3 comments · 2024-12-02Hacker NewsPydantic 2.0▲ 6 · 3 comments · 2023-06-30Hacker NewsPydantic 2 rewritten in Rust was merged▲ 4 · 2 comments · 2022-11-03Hacker NewsPydantic AI▲ 3 · 0 comments · 2024-12-03Hacker NewsPydanticAI using Ollama (llama3.2) running locally▲ 2 · 3 comments · 2024-12-06githubGitHub secret scanning — coverage update2026-03-31VentureBeatPython data validator Pydantic launches model-agnostic AI agent development platform2024-12-04TechCrunchSequoia backs Pydantic to expand beyond its open source data-validation framework2024-10-01