Software Development
Python 3.13 with optional GIL: what it means for teams
Free threading in Python became real with 3.13 and PEP 703, which makes the GIL optional at build time: the standard binary keeps it, while the separate python3.13t binary removes it. Thread-heavy orchestration code gains most; NumPy-style work that already released the GIL barely changes. Single-thread performance on that build drops around 40 percent.