Free-threaded CPython is ready to experiment with! The Python 3.13 beta releases that include a "free-threaded" version that removes the GIL are now available to test! A team from Quansight Labs, home of the PyData core team, just launched py-free-threading.github.io to help document the new builds and track compatibility with Python's larger ecosystem.
Free-threading mode will not be enabled in Python installations by default. You can install special builds that have the option enabled today - I used the macOS installer and, after enabling the new build in the "Customize" panel in the installer, ended up with a /usr/local/bin/python3.13t binary which shows "Python 3.13.0b3 experimental free-threading build" when I run it.
Here's my TIL describing my experiments so far installing and running the 3.13 beta on macOS, which also includes a correction to an embarrassing bug that Claude introduced but I failed to catch!
Recent articles
- OpenAI are quietly adopting skills, now available in ChatGPT and Codex CLI - 12th December 2025
- GPT-5.2 - 11th December 2025
- Useful patterns for building HTML tools - 10th December 2025