C code that doesn’t call into the CPython runtime isn’t constrained by the GIL. With 3.13t, conventional Python programs can now enjoy the same freedom. Cython 3.1 adds basic support for 3.13t.

Exploring new features in Cython 3.1 The next, still-under-wraps version of Cython offers powerful new features to convert Python to C and make existing C code easier to use. See how they work.