---
id: beartype
version: "0.22.9"
license: MIT License Copyright (c) 2014-2025 Beartype authors. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the… (full text in the JSON record)
license_treatment: permissive
maintenance: active
---

# beartype — Unbearably fast near-real-time pure-Python runtime-static type-checker.

License: permissive · Maintenance: active · Popularity: top 1,000 on PyPI

## Install

pip install beartype
uv add beartype
poetry add beartype

## Description

.. # ------------------( LICENSE                             )------------------
.. # Copyright (c) 2014-2025 Beartype authors.
.. # See "LICENSE" for further details.
.. #
.. # ------------------( SEO                                 )------------------
.. # Metadata converted into HTML-specific meta tags parsed by search engines.
.. # Note that:
.. # * The "description" should be no more than 300 characters and ideally no
.. #   more than 150 characters, as search engines may silently truncate this
.. #   description to 150 characters in edge cases.

.. meta::
   :description lang=en:
     Beartype is an open-source pure-Python PEP-compliant constant-time runtime
     type checker emphasizing efficiency and portability.

.. # ------------------( SYNOPSIS                            )------------------

=================
|beartype-banner|
=================

|rtd-badge| |ci-badge| |codecov-badge|

    ⚠

    `Beartype documentation lives at ReadTheDocs (RTD) <beartype RTD_>`__. It's
    readable, structured, and soothing to the deep folds of your big galactic
    brain. Open your mind to an ocean of mundane knowledge that will exhaust
    you at work. Enter... **the...

## AI interpretation — verify before relying

Beartype is a pure-Python runtime type checker that validates type hints on functions, classes, and variable assignments with minimal performance overhead, supporting PEP-compliant annotations and custom validators.

Verdict: Beartype is a production-ready, actively maintained type checker with zero dependencies, permissive MIT licensing, and no known vulnerabilities. Its low install friction and strong maintenance signal make it a reliable choice for runtime type validation in Python 3.10+ projects.

[View on SkillFed](https://skillfed.io/packages/beartype) · [View on PyPI](https://pypi.org/project/beartype/)