lean-qr

Lean QR is a lightweight yet fully-featured library for generating QR Codes. It runs in NodeJS and all recent browsers, and includes wrapper components for React and Preact. Under 4kB compressed.

Features

• ISO 18004 compliant;
• Lightweight (less than 4kB compressed, ~7kB uncompressed);
• Simple yet flexible API, with sensible defaults for all configuration;
• Supports all standard encodings out-of-the box (including Unicode and Shift-JIS);
• Automatic encoding to minimise output size;
• Fast enough for lag-free live editing;
• Multiple output formats (canvas / PNG / SVG / text).

You can see it in action online, or try it from the terminal:

npx lean-qr 'MY MESSAGE HERE'

Basic Usage

<canvas id="my-qr-code" />
<a href="#" download="qr.png" id="download-link">Download</a>

<style>
#my-qr-code {
  image-rendering: pixelated;
  width: 100%;
}
</style>

import { generate } from 'lean-qr';

const qrCode = generate('LEAN-QR LIBRARY');

// display in canvas:
qrCode.toCanvas(document.getElementById('my-qr-code'));

// provide a download link:
const dataUrl = qrCode.toDataURL({ scale: 10 });
document.getElementById('download-link')
  .setAttribute('href', dataUrl);

// display as text:
console.log(qrCode.toString());

Full Documentation

• Quickstart
• API Reference
• Migrating from Version 1.x to 2.x
• Source Code