Why are QR Codes with capital letters smaller than QR codes with lower-case letters?
shkspr.mobi
Take a look at these two QR codes. Scan them if you like, I promise there's nothing dodgy in them.     Left is upper-case HTTPS://EDENT.TEL/ and right is lower-case https://edent.tel/ You can clearly see that the one on the left is a "smaller" QR as it has fewer bits of data in it. Both go to the same URl, the only difference is the casing. What's going on? Your first thought might be th…

All uppercase text is unreadable and ugly as fuck. But it is what it is… if you typeset QR codes and can work within a small character set, you’re trapped with all uppers.

So then the question is, what can be safely converted to all uppercase without breaking? Apparently schemes, domain names and email addresses.

But what about the path? Nope, we’re fucked on that:

https://overflow.ocus.top/exchange/webmasters/questions/90339/why-are-urls-case-sensitive

OTOH, sometimes we get lucky

Ultimately a stupid decision by the QR designers indeed. Hence the cross-posting to [email protected]. The bulkier the text, the more useful it is to use the smaller char set. But the bulkier it is, the more unpleasant it is to read all uppercase.