Glossary
Payload
The payload is the actual string encoded in a QR code: the URL, the WIFI: block, the vCard. Everything about a code's size, density and minimum print dimensions follows from the payload's length and character set.
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Payload determines everything downstream
Length → version → module count → module size at a given print width → minimum scan distance. That chain is the whole of QR code engineering.
Payload prefixes
The leading characters tell a scanner what to do:
| Prefix | Action |
|---|---|
https: |
open in browser |
mailto: |
compose email |
tel: |
open dialler |
WIFI: |
join network |
BEGIN:VCARD |
add contact |
geo: |
open map |
upi:// |
open payment app |
| (none) | display as text |
Shortening a payload is free scannability
Before increasing size or error correction, shorten the payload. Removing 60 characters of UTM tracking from a URL can drop two versions, which makes every module ~15% larger at the same printed size. That is a bigger gain than any styling change.
Related
- Data capacity, Data capacity is how much a QR code can hold, and it depends on three things at once: the version, the error-correction level and the encoding mode. The…
- Encoding mode, Encoding mode is how characters are packed into bits. QR codes support numeric (3.33 bits/char), alphanumeric (5.5), byte (8) and kanji (13), and a single…
- Version, A QR code's version is its size: version 1 is 21 × 21 modules and each step adds 4 modules per side, up to version 40 at 177 × 177. The encoder picks the…