A QR (Quick Response) code is a two-dimensional barcode that stores data such as URLs, text, WiFi credentials, and contact info. Scanning with a phone camera instantly opens the encoded content.

Unlike traditional horizontal barcodes, QR codes store information in both vertical and horizontal directions, allowing them to hold much more data in a smaller space. They also natively support Error Correction (ECC), meaning that even if the code gets partially damaged, distorted, or dirty, a scanner can still perfectly recreate the missing data and successfully read it.