https://pydevtools.com/tags/mypy/ The Python Developer Tooling Handbook is a comprehensive guide to Python development tools including uv, ruff, pytest, mypy, ty, and more. Hugo -- gohugo.io en Sat, 09 May 2026 09:00:00 -0400 https://pydevtools.com/blog/mypy-2-0-parallel-type-checking/ Sat, 09 May 2026 09:00:00 -0400 Tim Hopper https://pydevtools.com/blog/mypy-2-0-parallel-type-checking/ <p>For most of the past year, the speed conversation around Python type checkers has had one shape: <a href="https://pydevtools.com/handbook/reference/mypy/">mypy</a> is the slow incumbent, and the fast alternatives (<a href="https://pydevtools.com/handbook/reference/ty/">ty</a>, <a href="https://pydevtools.com/handbook/reference/pyrefly/">Pyrefly</a>, <a href="https://pydevtools.com/handbook/reference/zuban/">Zuban</a>) earn their speed by being written in Rust. <a href="https://mypy-lang.blogspot.com/2026/05/mypy-20-relased.html"target="_blank" rel="noopener">mypy 2.0</a>, released May 6, 2026, takes a different route. It runs across multiple cores.</p> <h2>Run mypy across cores<span class="hx:absolute hx:-mt-20" id="run-mypy-across-cores"></span> <a href="#run-mypy-across-cores" class="subheading-anchor" aria-label="Permalink for this section"></a></h2> <p>The headline feature is <code>--num-workers N</code> (or <code>-nN</code>). Pass a worker count and mypy splits type checking across processes:</p>