QR Codes 101: What They Are and How They Actually Work

You've scanned hundreds of QR codes. Here's what's actually happening when you do.

It's just a really efficient way to store text

A QR code (Quick Response code) is a two-dimensional barcode. Where a traditional barcode only stores data in one direction (those vertical lines), a QR code stores data both horizontally and vertically in a grid of black and white squares — which is why it can hold far more information in the same amount of space.

Most of the time, that "information" is simply a URL. When your phone's camera recognizes the pattern, it decodes the grid back into that URL and offers to open it.

The three big squares aren't decoration

Look closely at any QR code and you'll notice three larger square patterns in three of the four corners. These are finder patterns — they let a scanner instantly figure out the code's orientation and boundaries, even if the code is rotated, tilted, or photographed at an angle. That's why you can scan a QR code from a poster across the room without lining it up perfectly.

There's also a smaller alignment pattern (usually near the fourth corner on larger codes) that helps correct for distortion, and built-in error correction that lets a code still scan correctly even if up to 30% of it is damaged, dirty, or covered by a logo.

Static vs. dynamic — the distinction that actually matters

A static QR code has the destination URL baked directly into the pattern itself. Once it's printed, it points to that URL forever — change your mind about the link, and you have to print a new code.

A dynamic QR code instead points to a short redirect URL that you control, which then forwards the scanner to your real destination. Change the destination anytime, and every already-printed code updates instantly — because the code itself never changes, only where it points.

Every QR code Snap generates is dynamic by default, which is also what makes scan tracking possible: we're the ones handling that redirect, so we can count it.

Why this matters for you

If you're printing something physical — a sign, a menu, a flyer — a dynamic QR code means a typo or a changed URL doesn't mean reprinting everything. It also means you can actually see whether anyone's scanning it at all, instead of hoping.