typing-extensions

typing-extensions provides backported and experimental type hints for Python, serving two purposes: enabling use of new type system features on older Python versions (e.g., TypeGuard from 3.10 is available on 3.9+), and enabling experimentation with new PEP-proposed typing constructs before they land in the standard library. The library also re-exports all names from the standard typing module, so it can serve as a single import source. Current version is 4.15.0 (as of early 2026); feature releases follow an irregular cadence under Semantic Versioning where only the major version is bumped for breaking changes.