What is a QR Code?

Tips & tricks
12 mins
QR code with a skull on it.

QR code stands for “quick response code”. They are a series of pixels in a square-shaped grid that conveys information when scanned. Originally used as an alternative to barcodes to track vehicle parts in manufacturing plants, they have gained widespread use as a way to open a URL on a mobile phone. This saves us from having to type long, complicated URLs into our browsers.

It also offers consumers contactless options for interacting in the physical world. For example, instead of providing physical menus, many restaurants place a QR code on the table. Patrons scan the code with their phone to be shown a menu on their screens. This type of contactless service has accelerated during Covid-19, removing the need to constantly disinfect physical menus or reassure people that they won’t contract the virus just by attempting to order their favorite cheeseburger.

[Get practical privacy tips. Sign up for the ExpressVPN Blog Newsletter.]

According to a 2020 survey by mobile-security platform MobileIron, 72% of users in the U.S. and several European countries have scanned a QR code recently, with 54% noticing an uptick in QR codes since the start of the pandemic. Meanwhile, 48% of respondents believe QR codes have security risks but continue to use them anyway. 

Jump to…

Who invented the QR code?
How do QR codes work?
Common types of QR code
How to scan QR codes with your phone
How to generate QR codes
Common uses of QR codes in daily life
Do QR codes collect my personal information and data?
Are QR codes secure? Here are the risks
Tips to stay protected
FAQ: About QR codes

Who invented the QR code?

The QR code system was invented by a Japanese engineer named Masahiro Hara for the company Denso Wave in 1994. He was tasked with creating a barcode that could track automobiles and automobile parts during manufacturing more easily. Hara got inspired by the board game called “Go Board” and invented the QR code with the help of his development team building the codes. At the time of the invention, they did not expect QR codes to be used beyond the automotive industry.

How do QR codes work?

QR codes work in the same way as barcodes at the supermarket. Each QR code stores information as a series of pixels in a square-shaped grid. When scanned, the QR code will open up a link, add contacts, send messages, or make calls for you. The whole process normally takes seconds.

What are the parts of a QR code?

A QR code typically consists of the following six elements:

  1. Quiet Zone: This is the blank area surrounding a QR code. It helps the scanning device differentiate the QR code from unrelated content that shouldn’t be scanned.
  2. Finder patterns: The finder patterns are the three identical square markers located in all corners of a QR code except the bottom-right corner. They allow the scanning device to recognize the QR code and determine the correct orientation. This allows your device to scan the QR code from different angles.
  3. Alignment pattern: The alignment pattern helps a scanning device compensate for moderate image distortions. This helps to orient the QR code when it’s too big. (You can occasionally find QR codes on billboards these days!). Not all QR codes have an alignment pattern.
  4. Timing pattern: The timing pattern is essentially two lines, one vertical and one horizontal, interconnecting the finder patterns in the three corners. It’s used to determine how large the data matrix is in the QR code.
  5. Version information: Did you know there are over 40 different versions of a QR code? Version information, which is some markers in a QR Code, specifies the version of a QR code. The most common versions are 1 to 7.
  6. Data cells: Data cells refer to the main part of a QR code consisting of black and white modules.

Input modes of QR code

A QR code encodes a string of text. The QR code standard has four modes for encoding text: numeric, alphanumeric, byte, and Kanji. Each mode encodes the text as a string of bits (1s and 0s) using different methods, all of which are optimized to generate the shortest possible string of bits for that data type.

  • Numeric mode: The numeric mode is used for decimal digits 0 through 9.
  • Alphanumeric mode: The alphanumeric mode is used not only for the decimal digits 0 through 9, but also the uppercase letters, symbols (e.g., %, $, and +) as well as a space.
  • Byte mode: In byte mode, the data string includes the mode indicator, the character count indicator, and then the raw bytes from the input text.
  • Kanji mode: Kanji mode is used for double–byte characters from the Shift JIS character set and is used to encode characters in Japanese, as the QR code was invented in Japan.

Static vs. dynamic QR codes

A static QR code leads to a destination that can’t be altered once generated. It has a fixed address to where it points you once scanned. If you want the QR code to point to a different destination, you’ll have to reprint the QR code.

Static QR codes are useful in mostly one-off uses where updates aren’t needed for the presented information. For example, a clothing shop owner can use a static QR code to embed its Christmas offers in posters around the shop.

On the other hand, a dynamic QR code leads to a destination that you can change. They often lead to shortened URLs that you can reconfigure at any time.

Common types of QR code

URL QR code

Type: Static or dynamic

A URL QR code turns a website or any landing page into a QR code. It’s one of the most common ways a QR code is used.

vCard QR code

Type: Dynamic

A vCard QR code is used on your business card or resume to give additional information about your clients or credentials. It can open up your personal or business website, or your LinkedIn profile.

File QR code

Type: Dynamic

File QR codes convert any files into a QR code. Such files include PDF, PNG, JPEG, or MP4. When scanned, the file will display or play on your device. File QR codes are dynamic.

Social media QR codes

Type: Static or dynamic

You can use social media QR codes in two different ways. See which way fits you best!

  • You can use a single social media QR code to house all your social media profiles in one place, usually on a landing page. This lets your customers follow your business on various social media platforms more easily.
  • Individual social media QR codes can be used to display your social media profiles separately.

H5 editor QR codes

Type: Dynamic

H5 QR codes display information in the format of a web page without the need of a domain host. This is especially useful when you have something small to promote and don’t want to create a website just yet, saving on time and maintenance cost.

Wi-Fi QR codes

Type: Static

Wi-Fi QR codes allow you to connect to a Wi-Fi network instantly. This means you don’t have to scroll through the list of networks to find the right one to connect to or type out the password manually.

App store QR codes

Type: Dynamic

An app store QR code opens the download screen for the app you’re trying to install on your device’s app store. It points you to the genuine app in case there are a few counterfeit versions lurking around on the app store.

Multi-URL QR codes

Type: Dynamic

Multi-URL codes are used to show different information depending on a number of factors, like the device’s language and location, the time of scanning, and more. They’re useful in running location-based or time-limited campaigns or showing localized content to a specific target audience. For example:

  • Let’s say you want to run a special promotion for your U.K. customers. You can use a multi-URL QR code to display promotional information to customers scanning the QR code from the U.K.
  • If you run a restaurant business, you can use a multi-URL QR code to display an appropriate menu, depending on the time of the day the QR code is scanned.

MP3 QR codes

Type: Dynamic

Promoting your latest music or podcast? You can convert it using an MP3 QR code.

Email QR codes

Type: Dynamic

An email QR code lets you send an email almost instantaneously (of course, you’ll still need to hit the “send” button yourself). But it will fill out all other information for you, like the receiver’s email address, subject line, and even the body text.

Text QR code

Type: Static

One of the most basic forms of QR codes, a text QR code displays a simple text consisting of words, numbers, and special characters. The good thing about it is that it doesn’t require an internet connection to work.

How to scan QR codes with your phone

To scan a QR code on your phone, all you need to do is to open up the Camera app. That’s right, you don’t need to download an additional app to do that anymore. Of course, this still requires a phone that has a built-in QR code reader. And most phones do these days.


  1. On your phone, open Camera.
  2. Point your camera at the QR code.
  3. Follow the instructions.


  1. On your phone, open Camera.
  2. Point the camera at the QR code.
  3. Follow the instructions in the banner that appears.

How to generate QR codes

There are mainly two ways to generate a QR code—through a QR code generator or the Chrome mobile app.

QR code generators

QR code generator websites let you convert a variety of things into QR codes, like URLs, files, and Wi-Fi. There are quite many QR code generators to choose from online. But be cautious of free ones, as they may start charging you after a certain number of scans are made.

The steps for creating a QR code with a QR code generator are generally like this:

  1. Visit a QR code generator website.
  2. Choose what you want to convert into a QR code.
  3. Download the QR code generated for your use.

Chrome mobile app

The Chrome mobile app can only convert webpages to QR codes. Also, they’re branded with Chrome’s pixelated T-Rex imagery. If you’re generating a QR code for your business, Chrome’s QR code generator may not be suitable for you.

Follow these steps to create a QR code on the Chrome mobile app.

  1. Open Chrome on your mobile device.
  2. At the top-right corner, tap the three-dot icon > Share.
  3. Tap QR Code.
  4. Tap Download.

Common uses of QR codes in daily life

QR codes are convenient, easy to use, and provide a quick response. That’s why they’ve become such an integral part of our everyday lives, facilitating the way we pay, travel, promote our business, and live through a pandemic.

For travel

Hotel check-ins often take a long time. Some hotels incorporate the use of QR codes and let guests check-in by scanning the code and filling in their arrival information. Also, sightseeing spots often provide tourists with QR codes to scan for more information.

For Covid-19

Some governments use QR codes in their contact tracing apps. Citizens can scan the QR code displayed at each venue to easily record the date and time of their visit. This helps them to know of any infected cases in the venue they visit. QR codes are also used to store vaccination records, ensuring compliance with vaccination requirements.

For payments

With QR codes, you can pay for things without having to take out your credit card or cash from your wallet. Most modern payment apps come with a QR code for others to scan and pay you or deduct money from you.

For marketing

You can use QR codes on your product packaging to offer tutorials or how-to videos. Want to grow your mailing list? Use the QR code on your brochures and flyers and let your customers subscribe with a quick scan. The good thing is, QR codes let you track metrics such as the number and timing of scans. This lets you measure the effectiveness of a campaign and plan for your next one.

For social media

Want to gain more followers on social media for your business? You can use a QR code to embed all your social media profiles in one place. Your customers can just scan the code and follow your pages instantly.

Do QR codes collect my personal information and data?

When you scan a QR code, its owner can receive basic information such as the time and location of the scan, and your device’s operating system. Apps that you use to scan QR codes could collect more personal information like your email address and phone number. In this case, it’s wise to get a sense of what personal data is collected before you scan a QR code with an app. Here are some important questions to consider:

  • What permissions does the app ask from you?
  • What personal data are you sending to and sharing with that app? (Although you may never know for sure, the permissions requested by that app may give you a clue.)
  • What data does that app share with and sell to third parties?

Are QR codes secure? Here are the risks

An increasingly popular attack vector is hacked QR codes containing malicious URLs. Once a user scans the code, they are redirected to a site with custom malware. Or the URL could be a phishing site that extracts as much information as possible from the affected user. 

Large corporations aren’t immune to this trend. QR codes on Heinz ketchup bottles have redirected people to porn websites, with the company blaming a lapsed domain as the reason for this faux pas. 

The relative ease of hijacking QR codes and inserting a malicious URL or payload is demonstrated in this YouTube video

Tips to stay protected

QR codes are convenient, easy to set up, and pack a lot of information inside a relatively tiny image. We expect them to become even more ubiquitous, which is why it’s necessary that you always follow good security hygiene when using them.

Many of us know to open emails and links from people that we know and trust. A failure to do that puts you at risk for phishing or social engineering attacks. QR codes are no different. It’s O.K. to scan a code for a menu or information at your local gym, for example. But don’t go around scanning QR codes posted on the local neighborhood announcement board or a random flyer, for instance.

The next step is to always keep your devices updated. A malicious QR code could take you to a site containing malware. The best way to guard against that is to make sure that your devices are running on the latest operating system and that all essential security applications are updated. 

Lastly, just be prudent and don’t let your guard down. If you come across a competition advertising free money and it sounds too good to be true, then it probably is. Don’t scan the related QR code. Hackers thrive on human fallibility and indiscretion. 

Read more: How to tell if your webcam has been hacked

FAQ: About QR codes

Is Google QR code generator free?
How do I make a QR code for a link?
Can I scan a QR code without an app?
Do all phones recognize QR codes?
What is the safest QR app?
Phone protected by ExpressVPN.
Take back control of your privacy

30-day money-back guarantee

A phone with a padlock.
Enjoy a safer online experience with powerful privacy protection
What is a VPN?
I like to think about the impact that the internet has on humanity. In my free time, I'm wolfing down pasta.