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Kyushu

A self-hostable WASM sandbox for JavaScript workers

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HN · launched Jun 7, 2026 · 89 upvotes (top 10%) · 0 views

Niche: code execution sandboxes · 37 launches, 0 in the last 7 days · Explore this niche →

Category and tags
  • Horizontal
  • Dev tools
  • Developer
  • Not AI
  • Hobby / open-source project

Visit website ↗ Source listing ↗

More like this: all 37 launches in code execution sandboxes →

Could you build this?

No Developing a secure, self-hostable WebAssembly sandbox for executing isolated JavaScript workers demands deep expertise in systems programming, compiler/runtime runtimes, and low-level virtualization.

What it would actually take: Built with Rust using Wasmtime or Wasmer embedded with a lightweight JS engine like QuickJS or SpiderMonkey compiled to WebAssembly. The hard part involves designing strict deterministic memory limits, CPU cycle metering, secure capability-based POSIX/WASI virtualization, and thread pooling under high concurrency without sandbox escapes.

Discussion

20 comments analyzed.

Competitors mentioned: Cloudflare Workers (V8 isolates), Firecracker virtual machines, Service Workers, StackBlitz, iframe sandboxing

Concerns raised: Startup latency compared to Cloudflare Workers, Performance overhead from QuickJS layer, Sandboxing not as strong as Firecracker, Early and experimental stage, Untrusted code execution risks in plugin systems

Feature requests: Live reload for kyu dev, Migration path from Cloudflare Workers, Hybrid backup support for Cloudflare failover

Competitors

Other products that read as similar to this one : 3363 launches clear the similarity bar, closest 8 shown.

Attention rank: #313 of 3364 (itself plus its competitors, highest first, normalized so YC and Product Hunt are compared fairly).

Launched 221 days after the earliest competitor.

  • Blast · hn · 2026-08-28 · 11 upvotes · similarity 0.67
  • container · github · 2026-09-23 · 11 upvotes · similarity 0.66
  • moejs · github · 2026-09-24 · 8 upvotes · similarity 0.66
  • Endo Familiar, an O-cap based JavaScript agent sandbox · hn · 2026-04-23 · 13 upvotes · similarity 0.64
  • mistatic · github · 2026-09-11 · 7 upvotes · similarity 0.63
  • proposals · github · 2026-10-24 · 18 upvotes · similarity 0.62
  • ende · github · 2026-10-13 · 19 upvotes · similarity 0.61
  • Forge · hn · 2026-07-04 · 5 upvotes · similarity 0.61

Related data

The niche, labels, vibe code rating and competitor comparison on this page are analysis by Nicheloom. If you use them, please credit nicheloom.com. How you may use our data.