Reading a long wifi password aloud to a guest is tedious and error prone. Phones will join a network straight from a QR code, and making one takes a few seconds.
A wifi code is exactly as private as the password inside it. Anyone who can see it, including anyone in the background of a photograph taken in that room, can join the network. Printed and stuck on a wall, it is the same as writing the password on the wall.
For a cafe, a rental or a waiting room that is usually the intention. For your home, put guests on the guest network and leave the main one alone, so a code on the fridge cannot reach the devices that matter.
It is also worth knowing where the code was made. A generator that builds the image on a server has your network name and password on somebody else's machine before you ever see the result. This one is built in the page, so what you type stays with you.
Print the code at least 3 centimetres on each side, and 5 is better, so a phone can read it from arm's length. Keep the dark on light contrast and leave the white border around it. If you will laminate it or it will be handled, choose High error correction.
Scan it with two different phones before you display it. Choose the right security type, WPA or WPA2 for almost every modern network, and tick the hidden network box only if the network name is not broadcast. Place it near where people will use it, such as the guest room or by the router.
Yes. Both read wifi codes with the built-in camera, with no extra app.
No. Semicolons, colons, commas and backslashes are handled correctly, which is where some generators quietly produce a code that fails.
You will need a new code. The password is inside the code itself rather than looked up somewhere.
At least 3 centimetres on each side, and 5 if people will scan it from further away. Bigger codes are easier to read, never harder.