Python 3.14 Major New Features | Generated by AI
Major New Features in Python 3.14
Python 3.14, released on October 7, 2025, brings significant enhancements focused on performance, concurrency, debugging, and developer experience. Here’s a summary of the key additions:
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Deferred Evaluation of Annotations (PEP 649 & PEP 749): Function, class, and module annotations are now deferred by default, improving startup time and eliminating the need for string-based forward references. Use the new
annotationlibmodule to inspect them in various formats. -
Multiple Interpreters Support (PEP 734): The
concurrent.interpretersmodule enables running isolated Python interpreters within the same process for better parallelism without the GIL. Includesconcurrent.futures.InterpreterPoolExecutorfor easy pooling. -
Template String Literals (PEP 750): Introduce “t-strings” (e.g.,
t"Hello {name}") that createstring.templatelib.Templateobjects, allowing flexible processing of interpolated strings for tasks like sanitization or custom rendering. -
Safe External Debugger Interface (PEP 768): Zero-overhead attachment for debuggers to running processes via
sys.remote_exec(), with security controls. Great for production debugging without restarts. -
Experimental Tail-Call Interpreter: A new opcode dispatch using small C functions instead of a switch statement, offering 3-5% speedups on supported platforms (Clang 19+). Enable with
--with-tail-call-interp. -
Free-Threaded Python Maturity (PEP 703): Official support for GIL-free builds, with reduced single-threaded overhead (5-10%) and better C API stability. Includes context-aware warnings for threading.
-
Zstandard Compression (PEP 784): New
compression.zstdmodule for high-performance compression, integrated intotarfile,zipfile, andshutil. -
Asyncio Introspection Tools: CLI commands like
python -m asyncio ps PIDandpython -m asyncio pstree PIDto visualize running tasks, detect cycles, and debug async issues. -
Incremental Garbage Collection: Cycle GC now runs incrementally across two generations, drastically reducing pause times for large heaps.
-
Enhanced REPL: Default syntax highlighting and import auto-completion (e.g.,
import co<Tab>suggestscollections).
Other notable improvements include better error messages (e.g., keyword suggestions, async/sync mismatches), stricter regex rules, and optimizations like 10-20% faster asyncio and up to 6x faster base64.b16decode.
For full details, check the official release notes.
What’s new in Python 3.14
Python 3.14 Release
Real Python: New Features