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Cloudflare Python Workers reach general availability on Pyodide and WebAssembly

simonwillison.net Editor score 7/10

Cloudflare runs Python compiled with Pyodide in its V8-based workerd runtime, while the local tool simulates that stack in a 123 MB binary; threading and multiprocessing do not work in the WebAssembly VM. The implementation and runtime limitations help teams evaluate Python on Workers.

What: Cloudflare Python Workers are generally available after a two-year preview.
How: Python runs compiled to WebAssembly via Pyodide in Cloudflare's V8-based workerd runtime; multiprocessing and threading do not work in the WebAssembly VM.
Why it matters: Engineers can deploy Python on the Workers platform, with WebAssembly's lack of multiprocessing and threading as constraints to account for.

Pyodide brings Python compiled to WebAssembly into Cloudflare's workerd runtime. Sketched from the article's own text.

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