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

cohix

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.

jahala

Loving the customer testimonials :D .. If someone feels like an eli5 - What are the use-cases for something like this?

Nasser_CAD

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.

egorferber

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

tribal808

nice site design

evacchi

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

dupontcyborg

the customer testimonials were enough to earn my github star

binyu

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?

Lerc

It raises the interesting question of what is the best isolation for a browser side sandbox. Running a worker. Running a worker running a js implementation. Running a worker running a wasm module running a js implementation (quickjs) running some passed code. Running a worker running what kyu build runs. And then of course the possibility of a environment where you pass it an integer n and it geneates n levels of. Nested layers with a randomly chosen implementation at each layer. Security by obfuscurity, is that a thing? Might be fun to implent the kyu wasm files as an executable format on my dumb cli idea. https://lerc.neocities.org/ (Kyu seems to fight my autocorrect wanting to turn it into you)

zuzululu

so am I able to migrate my current cloudflare worker API to this ?