Free-Threaded Python: Why Python Devs Should Know About the ABI

Why should every Python developer know about the CPython ABI? This week on the show, we speak with Nathan Goldbaum about free-threaded Python and the changes to the Python Application Binary Interface.

Nathan recently joined the CPython core developer team and has been building community support for free-threaded Python. Nathan shares his NumPy background and his work on shipping a new DType in NumPy 2.0. He also discusses his work on PyO3 and leading the effort to support thread-safe Rust extensions for use with the free-threaded build of Python.

This episode is sponsored by PropelAuth.

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Topics:

• 00:00:00 – Introduction
• 00:01:51 – The evolution of Free-Threaded Python
• 00:03:42 – Changes to the Application Binary Interface
• 00:05:16 – Improving the garbage collector
• 00:07:04 – Why should developers know about the ABI?
• 00:11:31 – What has changed with ABI?
• 00:19:42 – Sponsor: PropelAuth
• 00:20:18 – Python 3.13 and the updated PyObject
• 00:23:15 – EuroPython talk - What Every Python Developer Should Know About the ABI
• 00:31:13 – How did you get involved with NumPy?
• 00:35:33 – Video Course Spotlight
• 00:37:24 – Working on NumPy conference talk
• 00:42:23 – LLMs, aesthetic taste, and intentional software design
• 00:43:16 – Working on NumPy 2.0, DTypes, and building the String DType
• 00:54:43 – The stages of intentional design
• 00:57:34 – How does it connect to working on the ABI?
• 00:59:11 – Rust, PyO3, and the Spinning Jenny Project
• 01:04:03 – What are you excited about in the world of Python?
• 01:05:23 – What do you want to learn next?
• 01:06:34 – How can people follow your work online?
• 01:06:50 – Thanks and goodbye

Show Links:

• What Every Python Developer Should Know About the CPython ABI - Quansight Labs
• What every Python developer should know about the CPython ABI - Nathan Goldbaum - YouTube
• Python Free-Threading Guide
• Unraveling Community Support For Free-Threaded Python - Lysandros Nikolaou & Nathan Goldbaum - YouTube
• Compatibility Status Tracking - Python Free-Threading Guide
• PEP 779 – Criteria for supported status for free-threaded Python
• PEP 703 – Making the Global Interpreter Lock Optional in CPython
• Memory Management in Python – Real Python
• Nathan Goldbaum - From no CPython C API experience to shipping a new DType in NumPy 2.0 - YouTube
• The yt Project: Home
• yt - PyPI
• The Recurse Center
• Working with Arrays of Strings And Bytes — NumPy v2.6.dev0 Manual
• NEP: add NEP-0058 for bytestringdtype by ngoldbaum · Pull Request #32433 · numpy/numpy
• PyO3: Rust bindings for the Python interpreter
• Quansight Labs - Blog
• Nathan Goldbaum - LinkedIn
• Nathan Goldbaum - ngoldbaum - GitHub

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