A QR code decoder is a tool that can read and interpret the information stored in a Quick Response (QR) code. A QR code is a two-dimensional barcode that consists of a pattern of black and white squares. It can contain a wide range of information, such as website URLs, contact information, and product information.

A QR code decoder works by scanning the QR code with the camera of a smartphone or other mobile device. The decoder then analyzes the pattern of squares in the code and converts it into a readable format, such as text or a web link. This information can then be used for various purposes, such as accessing a website, downloading an app, or adding a contact to a phone's address book.

QR code decoder tools can be found as standalone apps or integrated into other apps, such as mobile browsers and messaging apps. Many modern smartphones and mobile devices have built-in QR code readers, so users can simply point their device's camera at the code and the decoder will automatically activate.

Overall, QR code decoder tools provide a quick and convenient way to access information stored in QR codes, making them an increasingly popular method of sharing information in today's digital age.