Beartype is an open-source pure-Python PEP-compliant near-real-time hybrid runtime-static third-generation type checker emphasizing efficiency, usability, unsubstantiated made up jargon and thrilling puns.

Beartype brings Rust- and C++-inspired zero-cost abstractions into the lawless world of dynamically-typed Python by enforcing type safety at the granular level of functions and methods against type hints standardized by the Python community in non-amortized worst-case time with negligible constant factors.