@qrcodesdk/node

Node.js renderers for QRCodeSDK. Use this package with @qrcodesdk/core when you need a PNG Buffer for files, HTTP responses, downloads, email attachments, or other server-side integrations.

Runtime requirements

@qrcodesdk/node requires Node.js 22.0.0 or newer. Packed consumers are verified in CI on Node 22.0.0 and the latest Node 24.x release. Installation through another package manager does not mean that the package is verified under that package manager's JavaScript runtime.

Install

npm install @qrcodesdk/core @qrcodesdk/node

pnpm add @qrcodesdk/core @qrcodesdk/node

vp

vp add @qrcodesdk/core @qrcodesdk/node

deno

deno add @qrcodesdk/core @qrcodesdk/node

bun

bun add @qrcodesdk/core @qrcodesdk/node

yarn

yarn add @qrcodesdk/core @qrcodesdk/node

Render PNG output

import {qrcode} from '@qrcodesdk/core';
import {QRCodePNGRenderer} from '@qrcodesdk/node';

const png: Buffer = qrcode('https://qrcodesdk.dev').render(
  QRCodePNGRenderer({
    size: 8,
    margin: 4,
    colors: {
      colorDark: '#111827',
      colorLight: '#ffffff',
    },
    dotsOptions: {type: 'rounded'},
    cornersSquareOptions: {type: 'extra-rounded', color: '#7c3aed'},
    cornersDotOptions: {type: 'dot'},
  }),
);

QRCodePNGRenderer() returns a Node.js Buffer containing a square, fully opaque PNG image.

Options

| Option | Type | Default | Description | | ----------------------- | ---------------------------- | -----------------: | ----------------------------------------- | | size | number | 5 | Pixel size of each QR module. | | margin | number | 4 | Quiet-zone width in modules. | | colors.colorDark | string | '#000000' | Dark module color. | | colors.colorLight | string | '#ffffff' | Background color. | | dotsOptions | QRCodeDotsOptions | {type: 'square'} | Ordinary module shape and optional color. | | cornersSquareOptions | QRCodeCornersSquareOptions | {type: 'square'} | Finder-ring shape and optional color. | | cornersDotOptions | QRCodeCornersDotOptions | {type: 'square'} | Finder-center shape and optional color. | | image.source | Buffer | undefined | PNG bytes loaded by the caller. | | image.size | number | 0.4 | Relative centered image-box size. | | image.padding | number | 1 | Clear padding in QR modules. | | image.clearBackground | boolean | true | Clears modules behind the image. |

Colors must be six-digit hex values such as #111827. size must be a positive safe integer and margin must be a non-negative safe integer.

All feature colors inherit colors.colorDark when omitted. Curves are rendered with deterministic subpixel coverage and blended into the opaque background.

Prepared PNG images

Load PNG bytes before calling the renderer:

import {readFile} from 'node:fs/promises';

const logo = await readFile('./logo.png');
const png = qrcode('https://qrcodesdk.dev')
  .errorCorrection('H')
  .render(QRCodePNGRenderer({image: {source: logo, size: 0.3}}));

The renderer synchronously decodes and composites the provided buffer but performs no filesystem or network I/O. Only PNG source bytes are accepted.

Save to disk

import {writeFile} from 'node:fs/promises';

import {qrcode} from '@qrcodesdk/core';
import {QRCodePNGRenderer} from '@qrcodesdk/node';

const png = qrcode('https://qrcodesdk.dev').render(QRCodePNGRenderer());

await writeFile('qrcode.png', png);

Send an HTTP response

The returned buffer can be sent from any Node.js HTTP framework as image/png:

import {createServer} from 'node:http';

import {qrcode} from '@qrcodesdk/core';
import {QRCodePNGRenderer} from '@qrcodesdk/node';

createServer((_request, response) => {
  const png = qrcode('https://qrcodesdk.dev').render(QRCodePNGRenderer());

  response.writeHead(200, {
    'Content-Length': png.length,
    'Content-Type': 'image/png',
  });
  response.end(png);
}).listen(3000);

Package boundary

@qrcodesdk/node provides Node-specific renderers and does not replace @qrcodesdk/core. The core package still provides qrcode(), matrix generation, builder options, and shared styling normalization.

Public API

import {
  type QRCodePNGImageOptions,
  QRCodePNGRenderer,
  type QRCodePNGRendererOptions,
} from '@qrcodesdk/node';

Documentation

• @qrcodesdk/node
• Installation
• Render PNG in Node.js
• Customize QR Codes