What is a QR Code?
A QR (Quick Response) code is a two-dimensional barcode that stores information in a matrix of black and white squares. Unlike traditional barcodes that can only hold a limited amount of data in a single line, QR codes can store significantly more information in both horizontal and vertical directions.
How QR Codes Work
QR codes use a specific encoding pattern to store data. When you scan a QR code with a camera or scanner app, the software reads the pattern of squares and decodes the embedded information. This can be a URL, plain text, contact information, Wi-Fi credentials, or many other data types.
The three large squares in the corners of every QR code are called finder patterns. They help scanners quickly identify the orientation and boundaries of the code, enabling fast and reliable scanning from any angle.
A Brief History
QR codes were invented in 1994 by Denso Wave, a subsidiary of Toyota, to track automotive parts during manufacturing. The technology was designed to be scanned quickly — hence the name "Quick Response." While initially used in industrial applications, QR codes gained mainstream popularity with the rise of smartphones.
Types of QR Codes
There are two main types of QR codes:
Static QR Codes encode data directly into the pattern. Once generated, the content cannot be changed. They work independently of any service and never expire.
Dynamic QR Codes use a short URL that redirects to your actual content. This allows you to update the destination without reprinting the code, and also enables scan tracking and analytics.
Common Use Cases
- URLs — Link to websites, landing pages, or online menus
- Wi-Fi — Share network credentials without typing passwords
- Contact Cards — Share vCard information instantly
- Payments — Mobile payment systems worldwide
- Events — Digital tickets and calendar invitations
- Marketing — Product packaging, business cards, and advertisements
Error Correction
QR codes include built-in error correction, which means they can still be scanned even if part of the code is damaged or obscured. There are four levels of error correction: L (7%), M (15%), Q (25%), and H (30%). Higher correction levels allow more damage tolerance but require a larger QR code.
Getting Started with QrLens
Creating and scanning QR codes has never been easier. With QrLens, you can generate custom QR codes for 15+ types, customize their appearance, and scan any QR code instantly — all for free, with no signup required.