The term "QR code reader" generally refers to any kind of tool that reads information from a QR code. As of 2015, a smartphone can function as a QR code reader as long as it has an application that can read the code through the phone's camera.
There is a wide variety of QR code reader applications available for most smartphone devices, and users can download them from both the Google Play Store and the Apple iTunes store. Developers originally created QR codes to track the movement of vehicles during the manufacturing process. Because of its convenience, advertisers now use QR code technology for coupons and other campaigns.