Libraries Run Rust Inside Python (With PyO3)

I was a bit nervous about this trend when it started picking up because I care about Pyodide (Python running via WebAssembly) and libraries that use PyO3 might not work in Pyodide.

Thankfully that's now been mostly solved - you can compile and publish WASM builds of Rust or C extensions on PyPI now and a Pyodide can then use them.

Here's the WASM build of the Rust-including Pydantic-core package for example: https://pypi.org/project/pydantic_core/#pydantic_core-2.49.0...

This is a nice party trick! I use it to provide easy installation of software that is written in rust, but is primarily used by Python users. (e.g.: Biology tools) They can do `pip install <name>`, since some people prefer this over downloading executables/installers. Bonus: Maturin/PyO3 can build "manylinux" binaries automatically, which helps with the Linux ABI diaspora.

But does it work everywhere Python works? My main issue with this Rust move has always been compatibility. Python can be embedded and ran in a heck of a lot of places. What's the story when libraries that I may want to depend on are actually implemented in Rust and my target doesn't/can't handle the toolchain and there's no build target?

> reach for, a Rust extension does the work

ai; dr, sorry

How much of the existing PyPI ecosystem do you think could realistically work this way without package authors doing anything specifically for WASM?

It’s time to start figuring out how to block domains on hacker news. This slop is getting out of control. Who can read this? The first few sentences already induced a migraine.

They’re not running Rust they’re running machine code compiled with the Rust compiler. Like many other Python libraries such as numpy are running machine code compiled with C++, C or Fortran. That was always the case for Python and is its main selling point, it’s a slow but easy to write glue language that can make faster native code scriptable.

Also the article reeks of AI slop, it’s just trying to sell you a Rust course.

Why not just run C inside of Python?

This is for WASM, but you can also do it to use a Qt frontend via Python's PySide6 with a Rust backend, avoiding the need of Rust bindings for Qt.