Free-threaded Python: past, present, and future

At PyCon US 2026, CPython core developer Thomas Wouters detailed the free-threaded Python interpreter, which removes the Global Interpreter Lock (GIL) to enable true parallel thread execution. He traced the motivation from historical single-CPU designs to modern multi-core systems, noting that the GIL was originally the most efficient way to support threads but now limits performance. Wouters, who works on this at Meta, highlighted that while alternatives like rewriting in Rust or using multiple processes exist, they require significant data and code restructuring, making free-threaded Python a more direct path to leveraging multi-core hardware.