Leaning Technologies

Interested in our technologies, or in compilers, virtual machines and WebAssembly in general?

👉 Join our Discord!

Run AI code securely on any device

Website · Repository · Documentation · Changelog

Sandboxed server runtimes that run entirely client-side, on a Linux-compatible kernel in WebAssembly
Node.js and Rust, with Python in preview. Ruby and Go are in development
Ships bash, git, curl, ripgrep, fd and core Linux utilities, plus npm, npx and pnpm for Node.js
Runs the frameworks and build tools you already use, such as Next.js 16, Vite 8, React, Nuxt and Express
Real Linux process behaviour: pseudo-terminals, signals, /dev and /proc, and scripts that run as executables
Run multiple processes and threads concurrently, with memory that grows only as programs need it
Expose a running dev server at a public URL with Portals, WebSockets included
Persistent or ephemeral filesystem on OPFS or IndexedDB, with multiple independent virtual disks
Built for AI agent sandboxes, web IDEs, interactive tutorials and runnable documentation

A browser-based coding playground, fully client-side

Start from a framework template (Vite, React, Svelte, Vue, Next.js, Nuxt, Express) or clone any GitHub repository
Run Claude Code, Codex CLI and Pi, with Antigravity, OpenCode and more coming soon
File tree, code editor, terminal and live preview, with bash and git
Share what you build at a public URL with Portals
Embed it in your docs, tutorials or landing pages
Built on BrowserPod, at near-native speed with instant startup
Free and open source

A Linux virtual machine that runs entirely in the browser

Runs an unmodified Debian distribution, with many native development toolchains
Built on CheerpX, our x86 virtualization engine
Networking through Tailscale: reach your private network and, with an exit node, the internet
A graphical Alpine desktop with Xorg and i3
Works with Claude, using your own API key
Fork it to deploy your own, with custom images

Run virtual machines in your web apps

Website · Repository · Documentation

A JavaScript library that runs unmodified x86 binaries in any browser, client-side
An x86-to-WebAssembly JIT compiler that handles dynamically generated and self-modifying code
A virtual block-based file system and a Linux syscall emulator, enough to run complete Linux distributions
Sandboxed by WebAssembly and the browser, even for untrusted code
The engine behind WebVM
CheerpX for Flash runs Flash Player, so Flash content works in modern browsers
Free for personal and open-source projects

Real Java in the browser

Website · Repository · Documentation · Playground

A full OpenJDK distribution in WebAssembly, with a JVM that runs your bytecode unchanged
Supports Java 8, 11 and 17
Run existing applications, applets, Java Web Start apps, and Oracle Forms and E-Business Suite clients, from unmodified JARs
Integrate Java libraries in JavaScript, fully client-side
Swing and AWT interfaces drawn with HTML elements and canvases
One script tag loads it, from our CDN or your own server. Works in Chrome, Edge, Firefox and Safari
Browser extensions run applets and Java Web Start apps in Chrome and Edge, for 170,000+ users
1M+ sessions a month from our public CDN
An agent skill for coding agents bringing Java apps to the browser

An enterprise-grade, open-source C/C++ compiler for WebAssembly and JavaScript

Port C/C++ libraries and applications to the browser, with the right JavaScript interfaces exposed
Write high-performance web applications and WebAssembly components in C++
Built on LLVM/Clang and tracks upstream, with custom optimisations for speed and output size
Apache 2.0 licence with LLVM exceptions, the same as LLVM/Clang

Navigation Menu