{"library":"pydantic","type":"library","category":null,"description":"The most widely used Python data validation library. Powers OpenAI SDK, Anthropic SDK, LangChain, FastAPI, LlamaIndex, and hundreds of other libraries. V2 released June 2023 — a near-complete rewrite in Rust via pydantic-core, 4-50x faster than V1. Current version is 2.12.5 (Mar 2026). V1 security fixes ended June 2024. V3 planned roughly annually.","language":"python","status":"active","version":"2.12.5","tags":["pydantic","validation","python","data-models","fastapi","llm","type-hints"],"install":[{"cmd":"pip install pydantic","imports":["from pydantic import BaseModel, field_validator, model_validator\n\nclass User(BaseModel):\n    name: str\n    age: int\n\n    @field_validator('age')\n    @classmethod\n    def age_must_be_positive(cls, v):\n        if v <= 0:\n            raise ValueError('age must be positive')\n        return v","from pydantic import BaseModel, model_validator\n\nclass User(BaseModel):\n    name: str\n    age: int\n\n    @model_validator(mode='before')\n    @classmethod\n    def check_root(cls, values):\n        return values","from pydantic import BaseModel, ConfigDict\n\nclass User(BaseModel):\n    model_config = ConfigDict(from_attributes=True)\n    name: str","from pydantic_settings import BaseSettings\n\nclass Settings(BaseSettings):\n    api_key: str\n    model_config = ConfigDict(env_file='.env')"]},{"cmd":"pip install 'pydantic[email]'","imports":[]},{"cmd":"pip install pydantic-settings","imports":[]}],"homepage":"https://docs.pydantic.dev","github":"https://github.com/sponsors/samuelcolvin","docs":"https://docs.pydantic.dev","changelog":"https://docs.pydantic.dev/latest/changelog/","pypi":"https://pypi.org/project/pydantic/","npm":null,"openapi_spec":null,"status_page":null,"smithery":null,"compatibility":{"summary":{"python_range":"3.10–3.9","success_rate":100,"avg_install_s":3.4,"avg_import_s":0.35,"wheel_type":"wheel"},"url":"https://checklist.day/v1/registry/pydantic/compatibility"},"provenance":{"verified_status":"passing","verified_at":"Sat Jun 27","last_verified":"Sat Jun 27","next_check":"Mon Jul 27","install_tag":"verified"}}