QR Code Generation Guide
How to generate QR codes programmatically — libraries, best practices, and use case-specific patterns.
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Tags: QR code generation guide, generate QR code programmatically, QR code library
QR Code Generation Guide Part of our complete guide to this topic — see the full series. Generating a QR code is straightforward — a well-designed library handles the ISO 18004 encoding, module placement, and quiet zone. The QR code specification (ISO/IEC 18004:2015) defines the complete encoding standard. The nuance is in choosing the right error correction level, format output, and payload structure for each use case. --- What about QR Code Structure? Before generating, it helps to know what a QR code contains: Finder patterns — three large squares in corners; tell scanners where the code is Alignment patterns — smaller squares helping correct perspective distortion in large codes Timing patterns — alternating dark/light row and column for module size detection Format information —…
Frequently Asked Questions
How do I generate a QR code?
Use a QR code library to encode your payload (URL, text, or structured data) and render to Canvas, SVG, or PNG. In JavaScript, the qrcode package renders to Canvas or a data URL in two lines. Online generators also work for one-off codes — paste your URL and download.
What library should I use for QR code generation?
For JavaScript/Node.js, the qrcode package (npm) is the most-used option — it works in both browser and Node, supports Canvas and SVG output, and has no dependencies. Python projects typically use qrcode (pip) or segno. Go developers use the skip2/go-qrcode library.
How do I generate a QR code in Python?
Install qrcode with pip: pip install qrcode[pil]. Then: import qrcode; img = qrcode.make('https://example.com'); img.save('code.png'). For custom error correction level and box size, use qrcode.QRCode() with explicit parameters.
How do I generate a QR code in JavaScript?
Install the qrcode package: npm install qrcode. Then: import QRCode from 'qrcode'; const dataUrl = await QRCode.toDataURL('https://example.com', { errorCorrectionLevel: 'M', margin: 2 }). Assign the data URL to an img.src to display it.
How do I add a logo to a QR code?
Generate the QR code at error correction level H (30% recovery), then composite a logo image over the center. The logo should cover no more than 25–30% of the total code area. Use Canvas compositing: draw the QR code, then drawImage() the logo centered over it. The error correction compensates for the obscured modules.
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