Wi-Fi QR syntax
The WIFI: string format that lets a phone join a network from a scan.
A Wi-Fi QR code encodes a single structured string, originating from ZXing's conventions and now supported natively by iOS and Android:
WIFI:T:WPA;S:NetworkName;P:ThePassword;H:false;;T— security type:WPA(covers WPA/WPA2/WPA3),WEP, ornopassS— the SSID, exactly as it appears when joiningP— the password, omitted fornopassH—trueif the network is hidden
The escaping trap. The characters \, ;,
,, : and " must be backslash-escaped inside a field.
A password containing a semicolon terminates the field early in a generator that does not
escape, and the phone attempts to join with a truncated password — failing with no
useful error.
Security note. The password is in the pattern in plain text. Anyone who photographs the code has it. Use a guest network.
In practice
A guest house sets its Wi-Fi password to Coast;2026!. A generator that does not
escape the semicolon produces WIFI:T:WPA;S:Guest;P:Coast;2026!;; — and the
phone reads the password as Coast, then fails to connect with no useful error.
Correctly escaped it reads P:Coast\;2026! and joins first time. Because the
failure is silent and looks like a router problem, this one costs people a surprising
amount of time.
Questions
Why does my Wi-Fi code fail on one phone but not another?
Usually the security type. A network running WPA3-only can be refused by devices
expecting WPA2 when the code specifies the wrong type. WPA covers the family
and is the safer value.
Can I make a Wi-Fi code dynamic?
Not directly — joining a network is not a URL. The workaround is a dynamic code pointing at a page on your site that displays the current credentials, which lets you rotate the password without reprinting.