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A browser-native operating system

Unix/Linux reimagined where the browser IS the kernel and Web APIs ARE syscalls. 60+ commands, bash-like shell, virtual filesystem, and IndexedDB persistence.

Open Source · MIT License

lifo -- bash

Try commands like help, ls, echo "hello", or neofetch

TypeScript60+ CommandsVirtual FSIndexedDBMIT License

Why Lifo?

AI agents need a sandbox

AI-generated code needs to execute somewhere safe. As agents write and run code autonomously, secure sandboxing is no longer optional — it's a requirement.

Cloud sandboxes are expensive

Spinning up cloud VMs for every execution is costly and slow. Browsers already have powerful, isolated environments — why not use them?

Vibecoding needs OS-level APIs

Vibecoding in the browser needs filesystem, shell, and process APIs. The browser already has it all — Lifo just maps them to familiar interfaces.

VMs are slow, Lifo is instant

VMs are slow to load because they secure and provision resources. Lifo runs instantly — it doesn't allocate resources, it just maps browser APIs.

What Lifo Is

A library that gives browser APIs a Linux-like interface for your agents.

Linux-like API

Wraps IndexedDB, Fetch, and Web Workers behind familiar POSIX/Unix-style interfaces. Work with files, processes, and networking using APIs you already know.

Node.js Compatibility

Shims for fs, path, process, and child_process. Run Node-style scripts directly in the browser.

What Lifo Is Not

✗Not a virtual machine

✗Not a full operating system

✗Not a Docker replacement

✗Not a server-side runtime

Lifo is a browser library that provides Linux-like APIs on top of existing Web APIs. It runs entirely in your browser tab — no backend, no VM, no containers.

Lightning Fast

~0ms

Boot Time

Cloud Round-trips

Infra Cost

Quick Start

$ npm install @lifo-sh/core

How Lifo Compares

Feature	Lifo	WebContainers	Cloudflare Sandbox	Vercel Sandbox
Runs in	Browser tab	Browser (WASM)	Edge worker	Cloud VM
Boot time	Instant (~0ms)	Moderate (~2-5s)	Fast (~50ms)	Slow (~1-5s)
Network required	No	Yes (to load)	Yes	Yes
Cost	Free (client-side)	Commercial license	Per-request pricing	Per-execution pricing
Offline support	Yes	No	No	No
Real filesystem	Virtual (IndexedDB)	In-memory	Limited	Full (ephemeral)
Node.js compat	Partial (shims)	Near-full	Workers API	Full
Licensing	MIT (open source)	Proprietary (commercial license required)	Proprietary SaaS	Proprietary SaaS
Best for	AI sandboxing, demos, prototyping	Browser IDEs, tutorials	Edge compute, API workers	Full backend execution

Use Cases

🤖

AI Agent Sandboxing

Let AI agents execute generated code safely in a browser sandbox. No cloud VMs, no security risks.

📖

Interactive Tutorials

Build zero-setup coding tutorials where learners run real commands directly in the browser.

💻

Browser-Based IDEs

Power browser IDEs with a real filesystem, shell, and process model. No server required.

⚡

Rapid Prototyping

Spin up environments in milliseconds. Test ideas instantly without provisioning infrastructure.

📡

Offline-First Apps

Build apps that work without internet. Files persist in IndexedDB across sessions.

🎓

Educational Platforms

Teach Linux, shell scripting, and system concepts without requiring students to install anything.

Features

📁

Virtual Filesystem

POSIX-like VFS with directories, files, symlinks, and permissions. Backed by IndexedDB for persistence across sessions.

🐚

Bash-like Shell

Pipes, redirects, command chaining (&&, ||, ;), environment variables, and tab completion out of the box.

⚡

60+ Commands

ls, cat, grep, awk, sed, curl, tar, git-like ops, and more. Familiar Unix tools running entirely in the browser.

🟢

Node.js Compat

Shims for fs, path, process, and child_process. Run Node-style scripts without a server.

💾

IndexedDB Persistence

Files and state survive page refreshes. Your virtual filesystem persists automatically in the browser.

📦

Package Manager

Install and manage packages directly in the browser environment with a built-in package manager.

58+ Built-in Commands

Familiar Unix tools running entirely in the browser

lscatcpmvrmtouchmkdirrmdirlnchmodchownstatfilefindtreedudfrealpathdirnamebasenamemktempgrepsedawksortuniqwcheadtailcuttrrevnldiffteexargsprintftarzipunzipgzipgunzipenvunamehostnamewhoamiuptimefreedatecalsleepyeswhichmanwgetpingdigbc

Limitations

No native binary execution

Only JavaScript and TypeScript can run. No compiled binaries.

.wasm support coming soon — ffmpeg, ImageMagick, SQLite and more

Virtual filesystem

Files live in IndexedDB, not on a real disk. Storage quotas vary by browser.

Mountable FS coming — local disk, cloud storage and more

No true process isolation

Processes share the main JS thread. Web Workers are available for parallelism.

Browser storage limits

IndexedDB quotas depend on the browser and available disk space.

No network sockets

Networking goes through the Fetch API. No raw TCP/UDP socket access.

Tunneling in progress — run Next, Expo, Express with real domains

Not for high-security sandboxing

If you need full VM-level isolation, use a cloud sandbox instead.

Roadmap

Git Integration

In Progress

Full git support via isomorphic-git. Clone, commit, push, and pull directly in the browser.

Port Exposing

Planned

Tunnel local ports to real domains. Run dev servers and access them from anywhere.

Run Full Projects

Planned

Run frameworks like Next.js, Express, Expo, Hono, and OpenClaw directly in the browser sandbox.

Wasm Runtimes

Planned

Python, ffmpeg, ImageMagick, SQLite, and Postgres compiled to WebAssembly for native-speed execution.