Show HN: Kyushu – A self-hostable WASM sandbox for JavaScript workers

Very cool work.

What approach are you using? Been working on a similar in-browser node runtime based on Rust/WASM kernel + Service-Worker HTTP intercept + CJS→ESM transform.

Feature wise, does this compare to StackBlitz webcontainers?

related: "Kefka is a Go-native shell sandbox with coreutils, Python via WebAssembly, and more" https://xeiaso.net/blog/2026/dancing-mad-sandboxing/

I started working on Nasscad back in early March with the assistance of Claude AI, and it led to Nasscad: a lightweight, powerful, and uncompromising CAD tool. I used to be allergic to HTML, Node.js, and the like. But we have to face the reality that the web stack dominates now—bringing along HTML, CSS, JavaScript, Wasm, frontend, and backend.

I’ve worked with Wasm for about 6 years now (founded a company around it that got acquired, even)

Even though our product was not a commercial success ~3 yrs ago I still believe something like this should succeed and give people choice when it comes to isolation/virtualization (containers, microVMs, Wasm). They are each useful and appropriate for different things.

Loving the customer testimonials :D ..

If someone feels like an eli5 - What are the use-cases for something like this?

the customer testimonials were enough to earn my github star

cool idea of a self-hostable alternative ot CF workers without much overhead, compiling it down to a binary makes local testing way easier.

nice site design

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