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QR codes

Everything you need to know about QR codes.

Published This article is more than 2 years old.
Reuters/Maxim Shemetov
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  • How do you like me now?

    After a decade of mockery and dismissal in the West, QR codes—those little black-and-white square patterns you scan with your phone to pull up a website—are finally having their moment.

    During a pandemic, nobody wants to touch anything. Reopened restaurants replaced paper menus with QR codes (and used the digital patterns to rescue soda machines). PayPal and Venmo rolled out a touchless payment option for businesses powered by QR codes, and CVS quickly announced plans to roll them out at 8,200 stores by the end of 2020.

    Pharmaceutical companies even began developing Covid-19 testing apps that display users’ health status via QR codes.

    For much of the rest of the world, the sudden proliferation of little black squares marks the unexpected vindication of a widely maligned technology.

    Open your camera app—we’re going to scan the history of a tool far ahead of its time.

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  • By the digits

    47%: Fraction of US and UK consumers who said they’ve noticed QR code usage on the rise since the start of the pandemic

    31,329: Maximum number of tiny squares you can cram into the largest QR code

    >65%: Share of the Chinese population using QR codes for mobile payments in 2017

    $143,000: Sum one Chinese hacker stole by pasting malicious QR codes on top of real ones

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  • Explain it like I’m 5!

    Image copyright: Reuters/Luisa Gonzalez
    China adopted QR codes ages ago. Now that rest of the world is wising up, will they stick?

    QR codes are a lot like the barcodes you see on product packaging and store shelves, except using a series of one-dimensional lines, a standard barcode, contains 20 characters of information, while the squares of a QR code allow them to fit thousands of characters of data.

    The other difference is that you can read a QR code using a camera instead of a laser.

    A standard QR code has three big squares, each occupying one corner. Those are alignment targets that help your phone’s camera see where the edges of the pattern are. A slightly smaller square in the remaining corner helps your phone make sense of the scale of the image and the angle at which you’re holding your phone.

    If you get bored enough during the pandemic, you could teach yourself to decode the little squares by hand—or you could just leave the work to a computer.

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  • Watch this!

    We all have the same question: Can you fit a whole game onto a single QR code? Short answer: yes! The largest QR codes can store about 3 KB of data, which, with a little finagling, is enough storage space to cram in a simplified version of the game Snake. Watch one programmer’s full journey to QR glory…or skip to 18:35 to see him hold the code up to his laptop’s camera and pop open the game.

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  • Brief history

    1971: An IBM engineer designs the Universal Product Code, which allows stores to begin using barcodes at checkout.

    1994: The QR code is born in the laboratories of Denso Wave, a subsidiary of Toyota, to help the automaker track car parts as they move down the assembly line.

    2000: A company called CueCat mails hundreds of thousands of cat-shaped barcode scanners to consumers so they can scan magazine ads to open companies’ websites.

    2010: Smartphones become smart enough to read QR codes—but only if you download a specialized scanner app.

    2011: Alipay introduces QR code payments to Chinese consumers.

    2014: Snapchat CEO Evan Spiegel visits China and is so impressed by WeChat Pay’s QR technology he immediately forms a team to create a proprietary version for his app; Facebook, Twitter, Spotify, and Amazon follow.

    2017: Software updates on iPhones and Android devices allow virtually all smartphones to scan QR codes using just their native camera apps.

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  • Million-dollar question

    Image copyright: Reurers/Jason Lee
    Smarter wallets.

    Shortly after QR code scanners debuted on smartphones, Chinese tech giants Alibaba and Tencent used the codes to launch mobile payments systems that now dominate the country’s retail experience.

    So why didn’t the codes spread outside China?

    Writing for the South China Morning Post, Karen Chiu posits that increasingly prosperous Chinese consumers had more of a need for mobile payments. The largest banknote was 100 yuan (about $16) and carrying around wads of cash was becoming cumbersome. Elsewhere, mobile payments didn’t take off; instead, the main use for QR codes became ill-conceived marketing campaigns.

    The QR divide is on full display during the pandemic. In China, Alibaba and Tencent once again rolled out a QR system for contact tracing via their widely used apps. Some countries, including Singapore, South Korea, and New Zealand, have followed its lead. Even American companies are trying to replicate the system—albeit on a purely voluntary basis.

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  • Morbid fact!

    A growing number of tombstones feature QR codes, which link to websites where mourners can upload photos, videos, and memories in a digital tribute to the dead.

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  • Take me down this 🐰 hole!

    In 2012, a fed up netizen created a Tumblr account to document the worst applications of QR codes in the wild (including codes affixed to bananas, sneakers, and employee uniforms). The blog was crowned the “definitive compendium of a sad and horrible technology” by tech reporters at Gizmodo.

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