What are they, what are they used for and how do they work?

You can find them printed on the packaging of a product; on a business card; at a restaurant table; in a supermarket; in a museum; in the field of crypto currencies; in advertisements or in medicine for information on certain diseases and in recent times included in the 'COVID passport'.



These 'quick response codes' (definition of the original Quick Response code in English) arrived as an evolutionary leap from barcodes and motivated by the need to increase the amount of information and possibilities of use of what they were capable of offering .



Although the vast majority of modules are formed in black and white, the standard admits some flexibility to add other colors. In these cases, the colors must maintain a sufficient contrast between light and dark so that it continues to be readable by code reading systems and programs.

What are QR codes used for? Since they can store different types of information, QR codes are used for many purposes. Among others:


Addresses: personal address, business address, etc.
Telephone numbers: personal or company telephone number.
Email addresses: personal or business accounts.
URLs with addresses of specific websites or web pages.
Links to apps, for example those that direct to the Google Play stores or the Apple App Store.
Payments: QR codes can store information about your bank account or credit card.
Authentication of online accounts. Websites can display a QR code that a registered user can scan with their smartphone and automatically log in.
Other various uses. For example marketing; to see the menu of a restaurant