Python 3.15.0 Alpha 2: Early Developer Preview Released

Python 3.15.0 Alpha 2 Released

Wednesday, November 19, 2025

We are pleased to announce the availability of Python 3.15.0 alpha 2, an early developer preview of Python 3.15. This release marks the second of seven planned alpha releases, offering a glimpse into the future of Python.

You can download Python 3.15.0 alpha 2 here.

Please note that Python 3.15 is still under active development. Alpha releases are designed to facilitate early testing of new features, bug fixes, and the overall release process. Features may be added until the beta phase begins on 2026-05-05, and may be modified or removed until the release candidate phase on 2026-07-28. As a preview release, it is not recommended for use in production environments.

Many new features for Python 3.15 are still being planned and implemented. Significant new features and changes introduced so far include:

• PEP 799: A new high-frequency, low-overhead, statistical sampling profiler and dedicated profiling package.
• PEP 686: Python now adopts UTF-8 as its default encoding.
• PEP 782: Introduction of a new PyBytesWriter C API for creating Python bytes objects.
• Improved error messages.

(To fellow core developers: If a feature you deem important is missing from this list, please inform Hugo.)

The next pre-release, Python 3.15.0a3, is currently scheduled for 2025-12-16.

More Resources:

• Online documentation
• PEP 790: 3.15 release schedule
• Report bugs at https://github.com/python/cpython/issues
• Help fund Python directly (or via GitHub Sponsors) and support the Python community.

And now for something completely different...

"An hour," said Ahab, standing rooted in his boat’s stern; and he gazed beyond the whale’s place, towards the dim blue spaces and wide wooing vacancies to leeward. It was only an instant; for again his eyes seemed whirling round in his head as he swept the watery circle. The breeze now freshened; the sea began to swell.

"The birds!—the birds!" cried Tashtego.

We hope you enjoy testing this new release!

A heartfelt thank you goes out to all the dedicated volunteers who contribute to Python Development and make these releases possible. Please consider supporting our efforts by volunteering your time or through organizational contributions to the Python Software Foundation.

Regards from a crisp and sunny subzero Helsinki,

Your release team: Hugo van Kemenade Ned Deily Steve Dower Łukasz Langa