Pydantic

Pydantic is Python's most-used data validation library: it enforces data schemas using standard type hints and boasts a Rust-core for exceptional speed.

Pydantic is the premier data validation and parsing library for Python. It mandates data structure using pure, canonical Python type annotations, drastically reducing boilerplate code. With over 360M monthly downloads, Pydantic is battle-tested: all FAANG companies and major frameworks (FastAPI, SQLModel, LangChain) rely on it for robust data handling. Its core validation logic is written in Rust, ensuring high performance. Pydantic models also generate JSON Schema, facilitating seamless integration and documentation for API development.

https://pydantic.dev