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How QR Codes Work: A Technical Guide

8 min read

Anatomy of a QR Code

QR Codes (Quick Response Codes) are 2D matrix barcodes consisting of black squares arranged on a white background. They can store up to 4,296 alphanumeric characters.

The Finder Patterns

The three large squares in the corners tell the scanner the orientation and size of the code, allowing 360-degree scanning.

Error Correction

QR codes use Reed-Solomon error correction, allowing them to remain readable even if up to 30% of the code is damaged. There are four error correction levels: L (7%), M (15%), Q (25%), and H (30%).

Data Encoding

QR codes support multiple encoding modes: numeric, alphanumeric, byte/binary, and Kanji. The mode is automatically selected based on your data for optimal storage.

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