How QR Codes Work: The Complete Technical Guide

What is a QR Code?

QR (Quick Response) codes are two-dimensional barcodes invented in 1994 by Denso Wave, a Japanese company. Unlike traditional barcodes that store data in one dimension, QR codes store data both horizontally and vertically.

How QR Codes Store Data

QR codes encode data using black and white squares arranged in a grid. The data is read by analyzing the pattern of these squares. QR codes can store:

• URLs and website links
• Plain text messages
• Contact information (vCards)
• WiFi network credentials
• Payment information
• Geolocation coordinates

QR Code Structure

A QR code contains several key components:

• Finder patterns: Three large squares in corners for orientation
• Timing pattern: Alternating modules for grid alignment
• Data area: The actual encoded information
• Error correction: Allows codes to be read even if partially damaged