A QR code is a square pattern of black and white dots that stores data, almost always a web link. Point a phone camera at it and the device decodes the pattern, then opens whatever sits behind it. No typing, no searching, just scan and go.
Think of it as a printed shortcut. Instead of telling a customer to open their browser and type a long URL, you put a small square on a poster, a receipt or a table card. They scan it and land exactly where you wanted, which is why QR codes took off for menus, event tickets and packaging. A well-made code can even open a deep link that jumps to one specific screen in an app rather than the home page. The pattern also carries error correction, so a code still scans even if part of it is scuffed, smudged or covered by a small logo in the centre.
Payments are a big use too. In the Netherlands a QR code on an invoice can open an iDEAL payment screen so the customer pays in a few taps, and wallets like Apple Pay use similar scan-to-pay flows in shops. The key is a destination that loads fast and works on a small screen, because a broken or slow link wastes the scan. A few practical rules help: keep the printed square at least two centimetres wide, leave white space around it, and always test the final printed version with a real phone before the run goes out. One untested code on ten thousand flyers is an expensive mistake.
At TopDevs we wire QR codes to trackable, controllable links so a client can see how many people scanned and change where the code points without reprinting anything.
