Create a Wi-Fi QR code that guests just tap

The format

Wi-Fi QR codes use a string format originally specified by the Java ME platform and now supported natively by every major mobile OS. The format is:

WIFI:T:<auth>;S:<ssid>;P:<password>;;

Where <auth> is WPA, WEP or nopass (open network). For a network called HomeWiFi with WPA2 and password letmein123, the string is:

WIFI:T:WPA;S:HomeWiFi;P:letmein123;;

The Smartees generator writes this for you when you pick the Wi-Fi encoding — you just type the three fields. The two trailing semicolons are required by the spec; some homemade generators drop them and scanners then fail to parse.

How scanning works on each OS

• iOS 11+: Open the Camera app, point at the code. A yellow notification slides down: "Join 'HomeWiFi' network". Tap to join.
• Android 10+: Same flow via the camera or Google Lens. Some manufacturers (Samsung) require enabling QR scanning in camera settings.
• Android 8-9: Use the Google app or Google Lens, not the stock camera.

Special characters in passwords

Three characters need escaping when they appear in the SSID or password: backslash \, semicolon ;, comma , and double-quote ". Each must be prefixed with a backslash. For example, the password p@$;w0rd becomes:

P:p@$\;w0rd

The Smartees generator handles this automatically. If you are hand-building the string, watch for these.

Hidden networks

For SSIDs that do not broadcast their name, add H:true before the trailing semicolons:

WIFI:T:WPA;S:HomeWiFi;P:letmein123;H:true;;

Without this, the scanning device will not find the network and the QR appears broken.

Where to put it

For a coffee shop, print the QR at A6 or A7 size and laminate it. Place it at customer eye level near the counter. For a home, a small frame next to the front door or by the guest bedroom works. For an event venue, A4 size by the entrance plus a smaller version on the printed programme covers both arriving and seated guests.

Security tradeoffs

A Wi-Fi QR code embeds your password in plain text. Anyone with a photo of the QR has your password. For your home network, this is generally fine — anyone close enough to photograph the code is already a trusted guest.

For a business, consider a separate guest network with its own password. Rotate the guest password monthly and regenerate the QR. The Smartees generator runs entirely in your browser, so the password never reaches any server.

Print sizing

Reliable scanning needs the QR to occupy at least 2 cm × 2 cm at 30 cm distance. For a wall-mounted display scanned from a metre away, scale to 7 cm × 7 cm. Always use error correction level M or higher; if you add a centre logo, use H.

Open the QR generator, pick "Wi-Fi", and you can print a guest card in under a minute.