Pyodide 314.0: Python packages can now publish WebAssembly wheels to PyPI
blog.pyodide.orgI've been looking forward to this for ages!
This means we can now take any C/Rust/whatever extension for Python, compile that as a `.wasm` extension, and then load it directly in browser Pyodide projects using:
await micropip.install("package-on-pypi")
import package_name
import micropip
await micropip.install("pydantic_core")
import pydantic_core
You can tell that it's got compiled code in (and not just Python) by running:
pydantic_core._pydantic_core
<module 'pydantic_core._pydantic_core' from '/lib/python3.14/site-packages/pydantic_core/_pydantic_core.cpython-314-wasm32-emscripten.so'>I had an older experimental Pyodide WASM project lying around (a packaging of the Luau language by Roblox) so I had Codex package that up for me and pushed it to PyPI.
Here's the package: https://pypi.org/project/luau-wasm/
And an interactive demo page where you can try it out: https://simonw.github.io/luau-wasm/import micropip await micropip.install("luau-wasm") import luau_wasm print(luau_wasm.execute(r''' local animals = {"fox", "owl", "frog", "rabbit"} table.sort(animals, function(a, b) return #a < #b end) for i, name in animals do print(i .. ". " .. name .. " (" .. #name .. ")") end '''))Wrote about this in more detail on my blog: https://simonwillison.net/2026/Jun/13/publishing-wasm-wheels...
`await micropip.install()` is starting to feel dangerously close to "just ship the whole universe to the browser."
Executing normal python programs inside a cpython vm inside a wasm context inside a javascript process inside a sandbox inside a browser is - genuinely - extremely exciting! (Might as well run the browser inside a container inside a VM while you're at it though.)
We heard you like runtimes, so we put a runtime in your runtime inside your runtime.
I'm sure everyone has seen this by now but just in case: https://www.destroyallsoftware.com/talks/the-birth-and-death...
This sounds like a solution looking for an unnecessary security nightmare.
Something as little as the runtime can just get exploited (which that as happened.) and cause a sandbox escape on the client side. There was a Chrome 0day at the runtime level which allowed untrusted code to run and escape the sandbox in the WASM runtime.
This complete worship of WASM (and their runtimes) as this magical silver bullet reminds me of the days and failures of Native Client (NaCL), Java Applets and Flash all over again.
You mean this one? https://theori.io/blog/a-deep-dive-into-v8-sandbox-escape-te...
I dunno, one sandbox escape in nine years is a pretty solid track record IMO.
Any reason WASM is more dangerous than regular JavaScript?
I presume this works (will work) also for JupyterLite that is based on Pyodide ? Would be great if it helped getting the latest OpenCV-python version [0] and it's dnn goodies being available on a zero-install client side Notebook !
Yeah it should definitely work there, anything you can `micropip.install()` into a Pyodide environment will work with JupyterLite.
Python in the browser keeps sounding ridiculous right up until it works.
Pyodide 314.0 is already available in xlwings Lite (the Python in Excel alternative you actually wanted).
Are u a curry fucker?
Great news. And indeed a nice step to an even broader Python ecosystem.
nice to see JS/python interop becoming a thing