Barcode and QR Code Reader

Point your camera at a code, or drop in a photo or screenshot of one, and read what it actually contains before you act on it. QR codes, product barcodes and the rest are decoded on your device, so the picture never leaves it.

What this is for

A QR code is unreadable to a person by design. That is fine when a code is printed on a menu you are already holding, and much less fine when one arrives in an email, is stuck on a parking meter, or has been pasted on top of the original on a poster. Reading the code before acting on it turns a leap of faith into an ordinary decision: you see the address, you recognise it or you do not, and only then do you tap.

It is equally useful for the dull cases. A product barcode becomes the number you need to type into a stock system. A ticket code becomes text you can paste into a booking reference. A Wi-Fi code from a cafe becomes the network name and security type in words, so you can join by hand when the automatic prompt does not appear.

Getting a picture it can read

Decoding is generous but not magical. Fill the frame with the code rather than the poster around it, keep all four corners inside the picture, and keep the camera square to the code where you can, since a steep angle squashes the pattern. Glare is the most common cause of failure on glossy paper: tilt slightly rather than adding light straight on. A screenshot is often better than a photograph, because it has no focus, no glare and no shake.

What it does not do

It does not tell you whether a link is safe, only where it goes. It does not join Wi-Fi networks or dial numbers on your behalf, because a web page is not permitted to do either, and would not deserve the permission if it were. It reads printed and on-screen codes, not the invisible watermarks some packaging carries. And it keeps nothing: reload the page and every code you read is gone, because none of it was ever stored.

The barcode was patented before the computer to read it existed

Norman Woodland worked out the idea on a Florida beach in 1949, drawing Morse code in the sand and pulling the dots and dashes downwards into thin and thick lines. He and Bernard Silver were granted the patent in 1952, then waited: no light source or computer of the era could read it cheaply. They sold the patent for 15,000 dollars. Two decades later the laser and the microprocessor arrived, and the first product ever scanned at a checkout, in Troy, Ohio in June 1974, was a ten pack of Wrigley's chewing gum. It is in the Smithsonian.