A couple of weeks ago I have met a new person.
When exchanging our contact details, I was going to ask his phone number... and he handed me over his phone and told me: scan this QR code!
I was really surprised. I did it, and voilà, I had his name and surname correctly spelled, address, phone number, and more.
So far, I knew that QR codes can contain URLs, but it's not just that.
When doing a few more investigations, I have found that they can contain up to 8 kbytes of data, that once encoded are about 3.000 8-bit characters.
You can encode multiple types of data, including URLs (see for example the QR code here above), email, SMS, and VCARDs.
Any library in any language can create these QR codes, but I chose the easy approach.
On the web, the top result from a Google search is https://qr-code-generator.com/, that allows to create some QR codes. There is a trial period, but I haven't understood for what.
When creating a QR code from this website, be sure to choose a Static Code (in the bottom of the page and by default collapsed). The Dynamic Codes are essentially links to their website.
QR Code Generator allows to place a custom picture at the center of your generated QR code, really very nice!
Another totally free alternative is https://goqr.me/.
This website is maybe less sophisticate, but it is really totally free, doesn't require any login registration and they guarantee to not store any of your data.
GoQR allows also to link a picture of you in the generated QR code (it must be already stored somewhere on the web).
The next level would be to use some prebuilt libraries and write custom code code to embed the data that we want.
I might create a dedicated app for this purpose in the future.