Python Version 3.14 Release: Speed, Syntax, and Features Guide

Python 3.14 brings meaningful improvements across performance, syntax, standard library enhancement, and introduces future-facing changes in architecture.

This release reflects the Python community’s continued commitment to developer productivity, robustness, and the long-term evolution of the language.

This article is your deep dive into everything new in Python 3.14, featuring hands-on examples and practical use cases.

Performance Improvements

Faster CPython

• Better function call handling
• Optimized reference counting and frame stack
• Improved memory allocatorperformance

Comparing Speed

from time import perf_counter

def compute():
    return sum(x * x for x in range(1_000_000))

start = perf_counter()
compute()
end = perf_counter()

print(f"Time taken: {end - start:.4f}s")

Template Strings (PEP 750)

PEP 750 introduces a new t"" string syntax for custom templating. This is different from f"" strings in that t"" strings allow a custom processor to evaluate and substitute content.

Why it matters:

• Allows libraries to hook into string formatting (e.g., for localization, logging, SQL generation).
• Supports domain-specific template systems.

from string import Template

# Using traditional string.Template
tpl = Template("Hello $name, you are $age years old.")
print(tpl.substitute(name="Alice", age=30))

t"Hello $name, you are $age years old."  # Conceptual syntax

Annotations: PEP 649 Deferred Evaluation (Again)

Python's default handling of function annotations returns to deferred evaluation. This means annotations are stored as strings in __annotations__ and evaluated only when needed.

Why it matters:

• Solves circular import issues.
• Makes introspection safer.
• No more reliance on from __future__ import annotations.

class Node:
    def __init__(self, value: int, next: "Node" = None):
        self.value = value
        self.next = next

print(Node.__annotations__)

{'value': 'int', 'next': 'Node'}

Zstandard Compression in gzip Module (PEP 784)

Python 3.14 adds support for the Zstandard compression algorithm, which is significantly faster than gzip and offers better compression ratios.

import gzip

data = b"Hello world!" * 100

# Write using zstandard compression
with gzip.open("example.zst", "wb", compresslevel=3, compressalgo=gzip.ZSTD) as f:
    f.write(data)

# Read it back
with gzip.open("example.zst", "rb") as f:
    print(f.read())

Free-Threaded CPython Preview (PEP 703)

Python 3.14 includes experimental support for free-threaded CPython, meaning Python can now run without the Global Interpreter Lock (GIL) in a special build configuration.

Why it matters:

• True multithreading is now closer to reality.
• Potential future standardization in Python 3.15+.

Note: You must compile CPython with --disable-gil to try this out.

import threading

def worker(n):
    for _ in range(n):
        pass  # CPU-bound task

threads = [threading.Thread(target=worker, args=(10_000_000,)) for _ in range(4)]

for t in threads:
    t.start()
for t in threads:
    t.join()

Error Message Improvements

Python 3.14 enhances error messages with more actionable context. For example, calling a function with the wrong type will show both types and source context.

def square(n: int):
    return n * n

square("hello")

TypeError: can't multiply sequence by non-int of type 'str'

New type.get_type_hints() Behavior

Python 3.14’s get_type_hints() from the typing module now reflects deferred annotations correctly, evaluates forward references lazily, and is consistent across runtime contexts.

from typing import get_type_hints

class Tree:
    def __init__(self, left: "Tree", right: "Tree"): pass

print(get_type_hints(Tree.__init__))

{'left': <class '__main__.Tree'>, 'right': <class '__main__.Tree'>}

New --install-debug-hooks CLI Flag

This new Python command-line flag enables all debug hooks like:

• tracemalloc
• faulthandler
• sys.setrecursionlimit
• warnings filters

python --install-debug-hooks script.py

from uuid import uuid7

print(uuid7())  # Time-based, sortable UUID

python3.14
>>> def greet(name): print(f"Hello, {name}")