What’s New in Python 3.14? Free Threading, JIT, and More

On October 9, the Python team released version 3.14, adding several notable features such as free threading support, the ability to use concurrent interpreters, improved debugger integration, and an optional new interpreter that can increase performance by 3%‑5%.

The free‑threading mode (disabling the Global Interpreter Lock) is fully implemented as described in PEP 703 , making concurrent Python programming more natural. This feature originated from Microsoft’s Faster CPython project, though Microsoft stopped supporting it in May.

Free‑threading is not enabled by default. On macOS it must be selected during a custom installation; on Windows it requires the new preview‑edition Python installer from the Microsoft Store. py install 3.14t After installation, use the python3.14t command to run the free‑threading build; otherwise the standard single‑threaded build is used.

Key new features in Python 3.14 include:

Template string literals (t"…") that return a template object, enabling custom parsing such as safe SQL query construction.

Support for multiple interpreters within the same process, offering performance and isolation benefits for certain concurrent workloads.

A new debugging interface allowing tools to attach to running Python processes without stopping them.

An optional interpreter that can improve performance by 3%‑5%.

Standard library support for Zstandard compression, a fast and efficient format developed by Facebook.

A new CLI for checking running Python processes with asynchronous tasks.

An experimental JIT compiler for macOS and Windows (not recommended for production and not supported in the free‑threading build).

Example of using a template string:

from string import Template

t = t'SELECT * FROM stocks WHERE ticker = {ticker}'
result = t.substitute(ticker="AAPL")
print(result)

The JIT compiler is experimental, may reduce performance in some cases, and does not work with the free‑threading build.

For a complete list of changes, see the official Python 3.14 release notes at https://docs.python.org/3/whatsnew/3.14.html.