Python QR Code Generator

What You'll Learn

In this comprehensive guide, you'll learn how to:

• Install and configure Python QR code libraries
• Generate basic QR codes in 5 lines of code
• Customize colors, sizes, and error correction
• Add logos and images to QR codes
• Batch generate QR codes
• Integrate into Flask/Django applications
• Deploy to production

Installation

Step 1: Install Python packages

pip install qrcode[pil]
pip install pillow  # For image manipulation

Step 2: Verify installation

python -c "import qrcode; print(qrcode.__version__)"

Basic QR Code Generation

5-Line Solution

import qrcode

qr = qrcode.QRCode()
qr.add_data('https://qrcodegeneratorjp.com')
qr.make()
img = qr.make_image()
img.save('qrcode.png')

Customization & Advanced Features

Custom Colors & Sizing

import qrcode

qr = qrcode.QRCode(
    version=1,
    error_correction=qrcode.constants.ERROR_CORRECT_H,
    box_size=10,
    border=4,
)

qr.add_data('https://example.com')
qr.make(fit=True)

img = qr.make_image(fill_color='#185FA5', back_color='white')
img.save('colored_qr.png')

Adding a Logo

from PIL import Image
import qrcode

# Generate QR code
qr = qrcode.QRCode()
qr.add_data('https://example.com')
qr.make()
img = qr.make_image(fill_color='black', back_color='white').convert('RGB')

# Add logo
logo = Image.open('logo.png')
qr_width, qr_height = img.size
logo_size = qr_width // 5
logo = logo.resize((logo_size, logo_size))

logo_pos = ((qr_width - logo_size) // 2, (qr_height - logo_size) // 2)
img.paste(logo, logo_pos, logo)

img.save('qr_with_logo.png')

Batch Generation

import qrcode

urls = [
    'https://example.com/1',
    'https://example.com/2',
    'https://example.com/3',
]

for idx, url in enumerate(urls, 1):
    qr = qrcode.QRCode()
    qr.add_data(url)
    qr.make()
    img = qr.make_image()
    img.save(f'qr_code_{idx}.png')

Flask Integration

Create QR Code API Endpoint

from flask import Flask, send_file, request
from io import BytesIO
import qrcode

app = Flask(__name__)

@app.route('/generate', methods=['GET'])
def generate_qr():
    data = request.args.get('data', 'https://example.com')
    
    qr = qrcode.QRCode()
    qr.add_data(data)
    qr.make()
    img = qr.make_image()
    
    # Save to BytesIO object
    img_io = BytesIO()
    img.save(img_io, 'PNG')
    img_io.seek(0)
    
    return send_file(img_io, mimetype='image/png')

if __name__ == '__main__':
    app.run(debug=True)

Usage: http://localhost:5000/generate?data=https://example.com

Error Correction Levels

Level	Recovery	Use Case
ERROR_CORRECT_L	7% damage	Clean indoor use
ERROR_CORRECT_M	15% damage	Standard use
ERROR_CORRECT_Q	25% damage	Harsh environments
ERROR_CORRECT_H	30% damage	Printed materials, outdoor

Best Practices

✅ Do's

• Use ERROR_CORRECT_H for printed materials
• Test generated codes on real devices
• Cache generated QR codes when possible
• Use high error correction for logos/images
• Maintain aspect ratio for logos

❌ Don'ts

• Don't make QR codes smaller than 1cm × 1cm
• Don't use low contrast colors
• Don't make logo larger than 20% of QR code
• Don't store sensitive data in QR codes
• Don't regenerate on every request (cache when possible)

Troubleshooting

Q: ImportError: No module named 'PIL'

A: Run pip install pillow

Q: QR code won't scan

A: Increase error correction: Use ERROR_CORRECT_H

Q: Logo placement is wrong

A: Ensure logo is smaller than 20% of QR code size

Q: How to track QR code scans?

A: Use URL shortener with analytics (bit.ly, TinyURL) or use our dynamic QR codes which provide built-in analytics

Generate Your QR Codes

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