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:
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.
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
'''))
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.)
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.
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 !
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:
Here's how to try the new feature out. Visit https://pyodide.org/en/stable/console.html and type: That gets you this WASM wheel: https://pypi.org/project/pydantic_core/#pydantic_core-2.47.0...You can tell that it's got compiled code in (and not just Python) by running:
I get this: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/Wrote about this in more detail on my blog: https://simonwillison.net/2026/Jun/13/publishing-wasm-wheels...
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.
[0] https://news.ycombinator.com/item?id=48421858