Notes Verified — Python 313 Release

>>> unknown_var NameError: name 'unknown_var' is not defined. Did you mean: 'unknown_var_x'?

In Python 3.13, you can compile CPython with the --disable-gil flag to produce a build. In this mode, multiple threads can execute Python code simultaneously on different cores.

The first thing you'll notice when launching Python 3.13 is a redesigned REPL (Read-Eval-Print Loop). Based on PyPy's implementation, the new interactive interpreter features multi-line editing, color support, and colorized exception tracebacks. This makes the REPL far more user-friendly for both beginners testing snippets and experienced developers debugging code. python 313 release notes verified

| Area | Improvement | |------|--------------| | list.append | ~10% faster due to reduced reference counting | | json module | Parsing speed up by 15-20% | | asyncio | Task creation and scheduling ~30% faster | | compile() | Bytecode compilation cache improvements |

It is crucial to manage expectations here. The performance team has been transparent that this is the foundation for future improvements. The speedups in this initial release are modest—in the range of 2–5% in many benchmarks—and the JIT is currently . To enable it, you must compile CPython from source with specific flags. This is not yet a feature you can simply toggle on in a standard installer, but its inclusion is the first step towards a future where Python code can run significantly faster. In this mode, multiple threads can execute Python

Python 3.13 adjusts its supported platforms significantly:

Python 3.13 is a significant release that includes several exciting new features, improvements, and bug fixes. The release notes have been verified through a thorough review and testing process, ensuring that the information is accurate and reliable. This document provides a comprehensive overview of the changes in Python 3.13, making it a valuable resource for developers and users. This makes the REPL far more user-friendly for

: A "copy-and-patch" JIT is included to provide the foundation for future performance gains. It is currently disabled by default and offers modest improvements in this initial stage. Improved Error Messages

>>> unknown_var NameError: name 'unknown_var' is not defined. Did you mean: 'unknown_var_x'? # actually useful now

While not offering massive speedups immediately, the JIT allows the interpreter to generate machine code on the fly for hot code paths.