Module
One square of the QR grid. A 25 × 25 code has 25 modules on each side. Print size is easiest to think about in modules.
Quiet zone
The blank margin around a code. Scanners use it to find the edge. The standard asks for 4 modules on every side, and QRotto includes it in every image.
Finder patterns
The three large squares in the corners. A scanner locates the code by them, and they have no error correction, so damage there breaks a code fastest.
Version
The size step of a code, from version 1 (21 × 21) to version 40 (177 × 177). Each step adds 4 modules per side. The tools pick the smallest version that fits.
Error correction
Extra data that lets a damaged code still read. Level L recovers about 7%, M about 15%, Q about 25% and H about 30%. Higher levels make the code denser.
Payload
The text inside a code, such as a link or a line starting WIFI:. The docs show the payload each tool writes.
Density
How many modules a code has. Denser codes have smaller modules at any print size and are harder to scan.
Static code
A code that holds its content directly. It cannot expire and cannot be edited. Every QRotto code is static.
Dynamic code
A code that holds a short address on a provider's server, which forwards to the real destination. It can be edited, and stops working if the provider stops it.
Escaping
Putting a backslash before a character that has a meaning in a format, such as ; in a WiFi code, so it is read as part of the text.
UTF-8
The way text is turned into bytes so that accents and other alphabets survive. All QRotto tools use it.
vCard
A standard format for contact details, starting BEGIN:VCARD. Phones offer to save it as a contact.
iCalendar event
A standard format for calendar entries, starting BEGIN:VEVENT or BEGIN:VCALENDAR. Phones offer to add it to a calendar.
Scheme
The start of a payload that tells the phone what to do: https: opens a page, tel: starts a call, mailto: an email, SMSTO: a text message, geo: a map.