A WebVM alternative for 64-bit Linux programs
Claude Code, Node 26 and every 64-bit arm64 program, with native engines where they fit.
Try it in your browser
npm i @uncontained/sdk yarn add @uncontained/sdk pnpm add @uncontained/sdk bun add @uncontained/sdk deno add npm:@uncontained/sdk Uncontained vs WebVM, side by side
WebVM runs on CheerpX, a JIT from 32-bit x86 to WebAssembly over a Linux-compatible syscall interface. It runs user-mode programs, without a Linux kernel.
| Capability | Uncontained | WebVM |
|---|---|---|
| Real Linux kernel | Yes, Linux 6.18 | No; a Linux-compatible syscall interface |
| Architecture | 64-bit arm64 | 32-bit x86 only |
| 64-bit tools (Claude Code, Codex, Bun) | Yes | No |
| Node.js | 26.13.0 on the browser’s JIT | Debian Buster’s nodejs, emulated |
| Native engines (no CPU emulation) | Native JS and Native Wasm | No |
| Network | Raw TCP, UDP and TLS through the relay | Through Tailscale |
| Licence | Ask Neutrium | Community licence; business use by quote |
WebVM facts are from Leaning Technologies (CheerpX)’s own pages, read on 10 November 2026.
When WebVM is the better fit
WebVM runs 32-bit x86 Debian programs today and streams disks from a CDN. If your binaries are 32-bit x86, it runs them as they are.
Questions about switching from WebVM
How fast is the emulated machine?
- Emulated runs our NWE engine; Node and Bun skip emulation and run on the browser’s JIT. A Claude Code turn takes 2.8 s on native JS against 6.7 s emulated.
Can it run x86 binaries?
- It runs arm64 Linux programs. Debian’s arm64 archive and vendors’ linux-arm64 builds cover the common tools.