2026-04-03 ยท 6 min read
How QR Codes Work
A practical explanation of what a QR code stores, how scanners read it, and why design decisions affect scanability.
A QR code is just structured machine-readable data
At its core, a QR code is a way to encode information into a square grid that mobile cameras and scanner apps can interpret quickly.
That information can be a web link, Wi-Fi credentials, contact details, payment data, or plain text. The scanner reads the pattern and hands the decoded result to the right app or action.
Why the pattern changes with content
A short URL usually produces a simpler pattern than a long paragraph or a full vCard. The more data you encode, the denser the pattern becomes.
Dense QR codes are still valid, but they can become harder to scan when printed small or styled too aggressively.
Why design rules matter
High contrast, enough quiet zone, and restrained logo usage are not cosmetic suggestions. They directly affect whether the code remains readable in the real world.
Leave clear space around the code
Avoid low-contrast foreground and background combinations
Keep center logos modest unless you also use stronger error correction