Read or make a QR code

When you need this

Two jobs, opposite ways round. Reading: somebody sends a screenshot with a QR code in it, and you cannot scan a picture that is already on your own screen with your own camera. Making: guests ask for the Wi-Fi password every single time they visit, or you want a code on a poster, a price list or a shop window that opens your WhatsApp.

How to use it

1. To read one, drop in the screenshot or photograph. The text inside is shown and you can copy it.
2. To make one, choose what it should hold — a link, some text, or your Wi-Fi details — fill it in and save the picture.

A Wi-Fi code worth printing

Put in the network name and password and you get a code that connects a phone when its camera is pointed at it. Print it small and leave it by the door or on the fridge. It saves reciting a password that has a zero and a capital O in it over and over.

It is only as private as the paper. Anyone who photographs the code has your Wi-Fi password, so keep it inside the house rather than on the gate, and see your home Wi-Fi router password for how to set a guest network instead.

What it does and does not do

• Reading happens on your phone. The picture is not uploaded, which matters when the code is a payment request or a ticket.
• It tells you what a code contains before you act on it. This is the safe way to check a code you do not trust — read it here and look at the link rather than scanning it with your camera, which may open it straight away.
• It does not shorten links or track scans. The code holds exactly what you put in, permanently. There is nothing to expire and no service to go out of business.
• Long text makes a dense code that cheap cameras struggle with. Keep links short and print the code larger rather than smaller.

Be careful with codes in the street

Stickers placed over real QR codes on posters, parking meters and payment signs are a known scam. Read the code here first and look at the address before you follow it — a mobile money request or a login page reached from a sticker is how people lose money. See mobile money scams and spotting fake messages and links.

If something goes wrong

• The code will not read. Crop closer to it, or take a sharper picture. Blurred, angled and very small codes all fail.
• The printed code does not scan. Print it bigger, keep white space around it, and do not print it on a dark or patterned background.