What is a qR code?
In one sentence: A square black-and-white pattern a camera can read, usually holding a web address; check where it goes before opening it.
A little more
A QR code is a square pattern of black and white modules that stores text, usually a web address. Three big squares in the corners help a camera find the code and work out which way up it is, and extra spare data (error correction) means it still scans when part is scratched or covered.
You cannot read a QR code by eye, which is exactly why tricksters like them: a sticker on a car park meter or a code in a message can send you to a fake page. Before you open one, look at the real web address it contains, and be extra careful if it asks you to pay or log in.
See it in action
- BonusCan a sticker change where a QR code takes you?Build a QR code and colour its parts (corner finder squares, timing lines, alignment square, format notes, message), scratch it, tear it and stick a price label on it while a real decoder tries to read it at four levels of spare data, then be the sticker detective: preview where five pretend posters really go, compare with the printed address and spot the fake.8 min · interactive
- 16How can you spot a fake message?Sort a pretend inbox of real and sneaky fake messages from games, banks, parcels and friends.7 min · interactive
- 2Anatomy of a web addressPaste any web address and see it taken apart, colour by colour: scheme, host, port, path, query and the fragment that never reaches the server.5 min · interactive
Do it for real
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