Static typing in Python becomes more expressive with new type hinting mechanics. Type Parameter Defaults (PEP 696)
If you are stuck on an ancient Linux distribution (e.g., CentOS 7 with OpenSSL 1.0.2), Python 3.13 will not compile or run without backporting a newer OpenSSL.
For decades, the has restricted Python threads from executing purely in parallel across multiple CPU cores. Python 3.13 introduces an experimental build mode that allows developers to run CPython completely free-threaded. python 313 release notes verified
Enables running without the GIL, allowing true CPU parallelism.
If you misspell a keyword argument in a function call, the traceback directly suggests the correct argument name. Static typing in Python becomes more expressive with
| Feature | Status | Verified Source | |---------|--------|-----------------| | New interactive REPL | ✅ Released | docs.python.org/whatsnew/3.13.html | | Experimental free-threaded build (PEP 703) | ✅ Released | PEP 703 + docs.python.org | | Experimental JIT compiler (PEP 744) | ✅ Released | PEP 744 + docs.python.org | | typing.TypeIs (PEP 742) | ✅ Released | PEP 742 | | Type parameter defaults (PEP 696) | ✅ Released | PEP 696 | | @warnings.deprecated (PEP 702) | ✅ Released | PEP 702 | | ReadOnly TypedDict (PEP 705) | ✅ Released | PEP 705 | | PEP 594 removals | ✅ Released | PEP 594 | | macOS 10.13+ support | ✅ Released | docs.python.org | | iOS/Android Tier 3 support | ✅ Released | PEP 730, PEP 738 | | mimalloc integration | ✅ Released | docs.python.org | | WASI Tier 2 support | ✅ Released | PEP 11 |
For decades, the Global Interpreter Lock (GIL) limited Python execution to a single CPU core per interpreter instance, crippling CPU-bound multi-threading. Driven by PEP 703 , Python 3.13 introduces an experimental build-time configuration to fully disable the GIL. What's New In Python 3.13 — Python 3.14.5 documentation Python 3
How to try it:
: 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
⚠️ Free-threaded mode: --disable-gil currently increases single-threaded overhead by ~5–10%.
: Users can now edit blocks of code directly in the REPL with history preservation.