picoqr

Ultra-lightweight, zero-dependency QR code generator for Node.js.

6.6 kB published (tarball) — built to embed into size-sensitive environments where every kilobyte counts.

Use Cases

• CLI tools — add QR output without inflating your dependency tree
• Thermal/receipt printers — BMP pixel data maps directly to ESC/POS raster commands, no image conversion needed
• Serverless functions — zero deps means near-zero cold start overhead
• Docker Alpine — pure JS, no native bindings, no node-gyp build step
• IoT / ARM devices — no cross-compilation issues

Why BMP?

Most QR libraries depend on canvas, libpng, or sharp for image output. These bring native bindings, platform-specific binaries, and painful installs on constrained environments.

BMP is an uncompressed bitmap format — encoding it is just raw pixel math. This is what keeps picoqr at zero dependencies. And for thermal printers (ESC/POS), raw bitmap is the native input format, making BMP the shortest path from QR matrix to printed output.

If you need SVG or PNG, use generate() to get the raw boolean matrix and render it yourself.

Install

npm install picoqr

API

generate(text, options?)

Returns a QR code as a 2D boolean matrix (true = dark module).

import { generate } from 'picoqr';

const matrix = generate('https://example.com');
// matrix[row][col] === true means dark module

toBuffer(text, options?)

Returns a QR code as a BMP image Buffer.

import { toBuffer } from 'picoqr';

const bmp = toBuffer('https://example.com', { scale: 8, margin: 2 });

toFile(text, filePath, options?)

Writes a QR code BMP image to disk.

import { toFile } from 'picoqr';

await toFile('https://example.com', 'qr.bmp', { ecLevel: 'M' });

Options

| Option | Type | Default | Description | |--------|------|---------|-------------| | ecLevel | 'L' \| 'M' \| 'Q' \| 'H' | 'L' | Error correction level | | scale | number | 10 | Pixels per QR module | | margin | number | 4 | Quiet zone width in modules |

CLI

npx picoqr "https://example.com" -o code.bmp

Usage: picoqr <text> [options]

Options:
  -o, --output <file>   Output BMP file path (default: qr.bmp)
  --scale <n>           Pixel scale per module (default: 10)
  --margin <n>          Quiet zone modules (default: 4)
  --ec <L|M|Q|H>        Error correction level (default: L)
  -h, --help            Show this help

Size Comparison

| Package | Deps | Install size | |---------|------|-------------| | qrcode | 41 | ~135 kB | | @paulmillr/qr | 0 | ~35 kB | | picoqr | 0 | ~6.6 kB |

QR Versions

Supports versions 1–15, covering up to 523 characters (EC level L). Handles URLs, WiFi configs, contact cards, and most real-world payloads.

Requirements

Node.js >= 20.0.0 (ESM only — no CommonJS require() support)

License

MIT