When a smartphone camera is pointed at a QR code, the process that follows is entirely local and surprisingly straightforward. No internet connection is involved at this stage; the phone is not reaching out to any server or external service. Instead, it relies solely on built-in software and image processing.
The moment the camera focuses on the QR code, it captures the image as a collection of pixels, much like taking an ordinary photograph. From there, the phone’s operating system activates a QR decoding algorithm that is already embedded in modern smartphones. This software uses local image processing to identify the distinctive square patterns that define a QR code. It adjusts for angles, rotation, or slight distortions caused by uneven surfaces or imperfect lighting. Once aligned, the decoder reads the grid of black and white squares and translates this visual pattern into binary data. The decoding itself is entirely offline — just like reading text from a photo.
That binary information is then converted into readable text. In many cases, the result is a familiar web address, such as https://example.com/some/page.
By this point, the phone has already completed its task: the QR code has been fully understood. The URL has been extracted successfully, all without using mobile data or Wi-Fi. In effect, the phone has simply read encoded text from an image—much like recognizing words printed on a page—demonstrating that scanning a QR code is an offline act long before the internet ever comes into play.