Legit Monorepo

Meet Legit SDK — fail-safe apps made simple.

Legit SDK is built around two core ideas: fail-safe by design, and effortlessly simple to use.

Fail-safe means giving your users the same superpowers you know from Git:

• Roll back to any previous state
• Branch off to run experiments safely
• Accept changes when you’re happy with the result

And it’s easy because you interact through the file system API (Legit FS) — the same one you learned in your first semesters of computer science.

Runs everywhere. Use Legit SDK as an API in the browser, or mount it as a folder on your machine. That means instant compatibility with the stack of your choice: Node.js, Python, Java… you name it.

Quick Links

• Documentation: Full guide and API reference
• Getting Started: Minimal example to get your first LegitFS repo up
• Example Starter: See a working editor demo with history tracking
• Contributing: How to contribute, including the Contributor License Agreement

Installation

npm install @legit-sdk/core

Minimal example

import { fs } from 'memfs';
import { initLegitFs } from '@legit-sdk/core';

async function main() {
  const legitFs = await initLegitFs(fs, '/');

  await legitFs.promises.writeFile(
    '/.legit/branches/main/hello.txt',
    'Hello world'
  );

  const history = await legitFs.promises.readFile(
    '/.legit/branches/main/.legit/history',
    'utf8'
  );
  console.log(content);
}
main();

Features

• Versioned filesystem – Every write is tracked in .legit
• Branching and history – Access past states, branch safely, merge confidently
• Interoperable – Works with Node.js, browsers, Docker, serverless, and more
• Extensible API – Compatible with custom storage backends

Project Structure

• packages/sdk/ – Source code of the SDK
• packages/sdk/dist/ – Bundled outputs for Node.js, browser, and TypeScript
• packages/sdk/src/compositeFs/ – Core filesystem abstraction
• packages/sdk/src/compositeFs/subsystems/ – Ephemeral, hidden, pass-through, and Git-backed file systems

Contributing

Please review the CLA before submitting contributions.

We welcome PRs, issues, and suggestions to make Legit SDK better for everyone.