QR code glossary
What the parts of a QR code are actually called and what each one does. Written from the specification and from behaviour we have tested, because several of these are the difference between a code that scans and one that does not.
302 redirect
A temporary HTTP redirect — the correct kind for a dynamic QR code.
Alignment pattern
Smaller nested squares that correct for distortion on larger codes.
Byte mode
The QR encoding mode used for general text, at 8 bits per character.
Deep link
A link that opens a specific screen inside an app rather than a web page.
Dynamic QR code
A QR code encoding a short redirect address you can repoint at any time.
Error correction level
How much of a damaged code can still be read: L 7%, M 15%, Q 25%, H 30%.
Finder pattern
The three large nested squares that tell a scanner where the code is.
Frozen code
A code over its plan limit that still redirects but cannot be edited.
GS1 Digital Link
A GS1 standard for encoding product identifiers in a web URL inside a QR code.
Micro QR code
A compact QR variant with one finder pattern, for very small marks.
Module
One square of a QR code — the smallest unit of the pattern.
Permanence Kit
An export of static fallback codes plus full data, so you can leave without reprinting.
QR code version
The size of the grid, from version 1 (21×21) to version 40 (177×177).
Quiet zone
The blank margin around a QR code — four modules minimum, per the spec.
Scan cap
A limit on how many scans a platform will record for you.
Short URL
The brief address a dynamic QR code encodes, which redirects onward.
Static QR code
A QR code with the destination encoded directly in the pattern.
Timing pattern
The alternating dark/light lines that let a decoder count modules.
UTM parameters
Query-string tags that let analytics attribute a visit to a campaign.
vCard
The standard contact-card format a QR code can encode directly.
Wi-Fi QR syntax
The WIFI: string format that lets a phone join a network from a scan.
If you only read three
Quiet zone, error correction level and module between them explain most of the reasons a printed code fails. The first is the margin designers crop, the second is the budget a logo eats, and the third is the measurement that decides how large you have to print.