How to Generate QR Codes for Websites and Apps

What Is a QR Code?

A QR (Quick Response) code is a two-dimensional barcode that encodes data — typically a URL — so it can be read by a smartphone camera. They're used in marketing, menus, app onboarding, authentication, and event ticketing.

What Can a QR Code Encode?

• URLs — https://example.com
• Plain text — any string up to ~4,000 characters
• Wi-Fi credentials — WIFI:S:MyNetwork;T:WPA;P:mypassword;;
• vCard / contact info — structured name, phone, email
• Email — mailto:user@example.com?subject=Hello
• TOTP / 2FA — otpauth://totp/... for authenticator apps
• Geo coordinates — geo:37.7749,-122.4194

Key QR Code Parameters

Error Correction Level

Level	Recovery	Use Case
L	~7%	Clean digital displays
M	~15%	General purpose
Q	~25%	Print with moderate wear
H	~30%	Logos embedded in QR

For most web use, M or Q is ideal. If embedding a logo over the QR, use H.

Size and Quiet Zone

• Minimum recommended print size: 2 cm × 2 cm
• Always include a quiet zone (white border) of at least 4 modules on each side
• For posters or high-DPI displays, export at 1000px or higher

QR Codes in App Onboarding

1. User opens desktop site
2. They see a QR code pointing to the App Store / Play Store link
3. They scan with their phone and download directly

Far more convenient than typing a URL or emailing yourself a link.

Generating QR Codes Programmatically (Node.js)

npm install qrcode

const QRCode = require('qrcode');

QRCode.toFile('output.png', 'https://konvertio.app', {
  errorCorrectionLevel: 'M',
  width: 500,
}, (err) => {
  if (err) throw err;
  console.log('QR code saved.');
});

Tips for Better QR Codes

• Test before printing — always scan with two different devices
• Use a URL shortener for long URLs — shorter data = easier to scan
• Avoid curved surfaces — distortion makes scanning unreliable
• High contrast is critical — dark on light background, never light gray on white
• Track scans — use UTM parameters to measure engagement

Generate QR Codes for Free

Use the free QR Code Generator on konvertio.app — enter any URL or text, customize the size and error correction, and download a high-resolution PNG instantly.