WiFi QR code
Enter the network name and password: generate a QR code that automatically connects to the WiFi when scanned.
What it's for
Super handy for homes, offices, B&Bs and cafés: print the QR, guests scan it with the camera and connect to the WiFi without typing the password.
Security
Everything happens in your browser: the password is never uploaded. The QR contains the password in clear, so only print it for people you want to connect.
What's inside the code
There's nothing magic about it: the QR holds a line of text in a format phones recognize, shaped like this — WIFI:T:WPA;S:network-name;P:password;;. The T is the security type, the S the network name, the P the password. Whoever points a camera at it sees a connection prompt and confirms with a tap: they never type the password and never see it.
Two details that break a hand-written code: the characters ; , : and the backslash inside the name or the password have to be escaped with a backslash in front, and a hidden network needs, at the end, H:true. Here it's all handled already, which is why generating it beats writing it.
The thing to decide before printing it
The QR contains the password in clear text: anyone who scans it, even out of curiosity, gets onto the network, and anyone who photographs it takes it away with them. Stuck up in a café or a waiting room it's fine; stuck up at home by the door it's like leaving the key under the mat.
The solution that settles the problem for good is the guest network: nearly every modern router has one, with a different password and no access to the household devices (the computer, the printer, the cameras, the network drive). You make the QR for that one, and the real password stays yours. If the router doesn't have one, it's at least worth changing the guest password now and then.
When it doesn't work
iPhone and Android cameras recognize this format on their own, without an app. The cases where it fails are nearly always three: the network is on 5 GHz and the phone is looking for 2.4 (or the other way round) with the same name; the network name contains accented characters or emoji, which some phones handle badly; or the QR is printed too small. For a code on a wall, ten centimetres a side is a size that always works.
Nearby tools
For a QR with an address, a text or a contact there is QR code generator, and to read a QR in front of you Read a QR code. For a strong password to put on the router the page is Password generator.