How Do QR Codes Work? A Simple Explanation
A QR code is a grid that stores text. Your camera reads the grid and opens it.
By James Dom 路 路
The grid
The three big squares are finder patterns so the camera can orient the code. The smaller modules are the data. qrfyy always uses error correction level M, which can survive a small mark. A large logo can still cover too much. Adding a logo does not raise the level.
Your phone
The camera app decodes the text. If it is a URL, the phone offers to open it. qrfyy builds that grid in the browser from whatever you type.
How much it can hold
A code comfortably holds a short URL, a WiFi string, or a contact card. It does not hold a PDF, a photo, or a video. Those stay on a server, and the code stores the link. Longer text makes a denser code that needs to be printed larger.
Why a small logo can still scan
Error correction repeats some of the data so a logo or a scratch does not erase the message. It is not unlimited. Cover the corners or most of the middle and the phone gives up. Keep logos small on qrfyy.
FAQ
Do I need a special scanner app?
Most modern phones read QR codes in the camera app. The qrfyy scanner is there if you want to check a code on a laptop.
Ready to create your own QR code?
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