ty: Python Type Checker & Language Server ty (v0.0.34, May 2026) is Astral's Rust-based Python type checker and language server. Beta status: 0.0.x versioning, breaking changes between versions, and no stable API yet. Astral reports 10-100x faster checks than mypy and Pyright on large projects. Formerly "Red-Knot" , renamed May 2025, extracted from the ruff repo to . When to Use ty - section in or exists - Type checking Python code in any project - Setting up an LSP for Python in your editor When to wait: Projects heavily dependent on mypy plugins (Pydantic, Django, SQLAlchemy). ty has no plu…