What actually happens when someone scans your QR code

Point a phone camera at a QR code and something opens a second later. Most people treat it as a small magic trick. It is not. A QR code is a link — the same link you would type into a browser — encoded as a grid of black and white squares so a camera can read it instantly.

It is a link, not a document

That distinction is the whole point. A printed card is a document: whatever is on the paper is what the reader gets, forever. A QR code is a pointer to a page, and a page can change. Your code stays the same while the page behind it stays current — new headline, new number, new photo, same code.

• The code holds your card's permanent link. In practice that is something like mykarrd.com/yourname.
• Nothing personal is stored in the code itself — no phone number, no email, no address.
• Scanning it opens your card in the phone's browser. No app, no account, no download for the person scanning.

Why your code keeps working after you change jobs

Say you print two hundred codes for a conference. A year later you have moved company and your phone number has changed. A paper card would now be wrong in two places. The QR code still opens your card, and what is written on the card is the version you updated this morning. When you edit your details, the printed code is still correct.

The four things that make a code fail

QR codes fail for boring physical reasons, and all of them are avoidable before you print:

1. 9.1Too small. Below roughly two centimetres on a printed card, and phones start to struggle. Leave real white space around the code.
2. 9.2Wrong colours. Dark on light scans. Light on dark is unreliable, and a printed code that only works in the design file is worse than no code.
3. 9.3No quiet zone. The white margin around the code is part of the design. Crop it and recognition rate drops.
4. 9.4Damage. Fold it, laminate it badly, wrap it across a curved surface, or let it get scuffed, and the code degrades. A flat sticker lasts better than a fold.

Before you print a thousand of them

1. 11.1Scan your code with the worst phone in the room. If it works there, it works everywhere.
2. 11.2Scan it in sunlight and again in a dim room, because the two are different problems.
3. 11.3Scan it from the distance a stranger would stand at — about arm's length.
4. 11.4Check that the link opens your card, not a login screen or a 404.

So the honest answer to what happens when someone scans your QR code: their camera reads a link, their browser opens your card, and they save your details in one tap. The rest is just print quality.