Complete Guide to QR Codes and Barcode Scanning: Generation, Types, and Real-Time Scanning

Quick Response (QR) codes and 1D barcodes bridge the physical and digital worlds. From mobile contactless payments and smart venue ticketing to inventory management and instant WiFi access, QR codes are ubiquitous.

In this article, we cover QR code error correction levels, data payloads (vCards, WiFi, URLs), and how real-time barcode scanning works in modern web applications.

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Anatomy of a QR Code & Error Correction (Reed-Solomon)

QR codes use Reed-Solomon Error Correction algorithms, allowing codes to remain readable even if up to 30% of the symbol surface is damaged, smudged, or covered by a custom logo:

• Level L (Low): 7% error recovery (best for small size).
• Level M (Medium): 15% error recovery (standard default).
• Level Q (Quartile): 25% error recovery.
• Level H (High): 30% error recovery (best when embedding center logos).

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Supported Barcode Symbologies

1. 2D Codes: QR Code, Data Matrix, Aztec, PDF417.
2. 1D Linear Barcodes: UPC-A, UPC-E, EAN-13, EAN-8, Code 128, Code 39, ITF.

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Generate & Scan QR Codes Online

• Create custom QR codes for URLs, vCards, or WiFi credentials with custom colors and center logos using our QR Code Generator (/tools/qr-code-generator).
• Scan any QR code or 1D barcode in real time using your webcam or uploaded file with our QR & Barcode Scanner (/tools/qr-barcode-scanner).