What the code actually contains

A WiFi QR code is not a link. Instead of a web address, the square holds a short piece of structured text describing your network: the SSID, the security type and the password. When a phone camera recognises that format it offers a "Join network" prompt rather than opening a browser. Nothing is uploaded, nothing is looked up, and no server is involved, which is why the code keeps working during an outage or in a basement with no signal.

Choosing the right security type

Almost every modern router uses WPA2 or WPA3, and both are covered by the WPA option. Choose WEP only for very old hardware, and choose the no-password option for a genuinely open network. Getting this wrong is the single most common reason a WiFi code appears to do nothing: the phone tries to authenticate with the wrong method and silently gives up. Hidden networks also need the SSID typed exactly, including capital letters, because there is no broadcast name for the phone to match against.

Where these codes earn their keep

Cafés and bars put one on the table so staff stop repeating a twelve-character password over the noise. Holiday rentals and small hotels laminate one in the welcome folder. Offices tape one inside reception for visitors. Waiting rooms and barber shops stick one on the mirror. In every case the value is the same: fewer interruptions for staff and a guest who connects in four seconds instead of forty.

Print it dark on a light background, keep a clear margin around the square, and give it at least 3 cm on a table card. If the network is used by anything that matters, put a separate guest network on the code and keep your working network off the wall.