Simon Willison’s Weblog

cibuildwheel 2.20.0 now builds Python 3.13 wheels by default (via)

CPython 3.13 wheels are now built by default […] This release includes CPython 3.13.0rc1, which is guaranteed to be ABI compatible with the final release.

cibuildwheel is an underrated but crucial piece of the overall Python ecosystem.

Python wheel packages that include binary compiled components - packages with C extensions for example - need to be built multiple times, once for each combination of Python version, operating system and architecture.

A package like Adam Johnson’s time-machine - which bundles a 500 line C extension - can end up with 55 different wheel files with names like time_machine-2.15.0-cp313-cp313-win_arm64.whl and time_machine-2.15.0-cp38-cp38-musllinux_1_2_x86_64.whl.

Without these wheels, anyone who runs pip install time-machine will need to have a working C compiler toolchain on their machine for the command to work.

cibuildwheel solves the problem of building all of those wheels for all of those different platforms on the CI provider of your choice. Adam is using it in GitHub Actions for time-machine, and his .github/workflows/build.yml file neatly demonstrates how concise the configuration can be once you figure out how to use it.

The first release candidate of Python 3.13 hit its target release date of August 1st, and the final version looks on schedule for release on the 1st of October. Since this rc should be binary compatible with the final build now is the time to start shipping those wheels to PyPI.