Serdar Yegulalp
Senior Writer

Go hands-on with Python 3.15

feature
Aug 21, 20263 mins

Experience first-hand the best that the upcoming version of Python has to offer, from its built-in JIT to powerful new data types.

Hands type on a laptop keyboard with lines of code visible on the display.
Credit: SeventyFour / Shutterstock

Python can’t stop, won’t stop evolving. Python 3.15, due in fall 2026 but available now in its first release candidate, abounds with useful new features worth trying out: lazy imports, a new profiling technology, immutable dictionaries, and its ever-evolving JIT (just-in-time) compiler.

Top picks for Python readers on InfoWorld

Speed boost your Python programs with new lazy imports
Don’t let a fat Python import be a bottleneck for the rest of your program. Lazy imports let you defer executing a module until the time it’s actually used. Best of all, you can use lazy imports with no changes to existing code.

Hands-on with the new sampling profiler in Python 3.15
It’s like X-ray goggles for your code! Tachyon, the new profiling system for Python, lets you see what your program is doing without having to instrument it, rewrite it, or even pause it and restart it.

Get started with Python’s new frozendict type
Python users have been clamoring for an immutable dictionary type, and now they’ve got one — built right into the language. Ever wanted to use a dictionary as a key for another dictionary’s value, or seal a dictionary against modification? Here’s your solution.

Get started with Python’s new native JIT
We all want faster Python, but nobody wants to rewrite their code. Python’s new built-in JIT is paving the way to automatically faster Python, and you can get started with it right now.

More good reads and Python updates elsewhere

Run Numba in the browser with WebAssembly
Numba speeds up computation in Python by compiling to native code, making it a tricky candidate for porting to an in-the-browser experience. Nevertheless, a new project from QuantStack, called JupyterLite, not only brings Numba into the browser but adds performance boosts too.

Mojo is now open source
The one-time Python challenger for the scientific computing space has shaped up to be a “Rust lite” language. And now it’s freely available under an Apache 2 license for your tinkering and forking pleasure.

Scaling NumPy on free-threaded Python
As Python’s free-threaded build gains traction, developers of libraries such as NumPy are working to squeeze maximum oomph from Python’s newfound parallelism. Learn how hidden bottlenecks in NumPy kept it from scaling, and what it took to break that stranglehold.

How a common string method in Python turned out to have a security vulnerability
When does converting a string into lowercase expose you to danger? When a corner case in how the operation is processed can deliver inconsistent results. Read about how this tiny but troubling problem was detected and fixed.

Serdar Yegulalp

Serdar Yegulalp is a senior writer at InfoWorld. A veteran technology journalist, Serdar has been writing about computers, operating systems, databases, programming, and other information technology topics for 30 years. Before joining InfoWorld in 2013, Serdar wrote for Windows Magazine, InformationWeek, Byte, and a slew of other publications. At InfoWorld, Serdar has covered software development, devops, containerization, machine learning, and artificial intelligence, winning several B2B journalism awards including a 2024 Neal Award and a 2025 Azbee Award for best instructional content and best how-to article, respectively. He currently focuses on software development tools and technologies and major programming languages including Python, Rust, Go, Zig, and Wasm. Tune into his weekly Dev with Serdar videos for programming tips and techniques and close looks at programming libraries and tools.

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