This was something that I paid close attention to when designing a QR code to be hand-carved into a set of coasters. To minimize the amount of detail carving required, I wanted to use the smallest QR code at 21x21 (version 1) tiles.
With ascii encoding, this would limit me to 17 characters, but the alphanumeric encoding allowed up to 25 characters. Since DNS is case-insensitive, this let me carve a slightly longer URL. The only downside was that it required making a custom redirect on my own website, since I couldn’t find any url shorteners that would use all caps.
To this day, it is the most effort I’ve put into rick-rolling somebody.
Redirects going anywhere is super flexible, but is also the unfortunate business model of so many "free qr code generator" sites which end up taking your destination link hostage...! (this just reminds me of that, obv the parent post isn't doing that)
My friend's partner once printed a qr code like that and then had to pay a monthly fee to keep the qr code working. Pure predator behavior.
My sister has run into this before as well. You have to be very careful because 99% of QR generators out there do something like that. I’ve found some that don’t for her to use but I really should just vibe code up a website for her that I know won’t do a bait and switch (obviously they can’t change old “pure” QRs but they could start doing redirects on new ones at any time).
A European gym chain hosts a very simple end-point for their entry QR codes — just a GET with the data in a query param — so I tend to use that one just because it somewhat amuses me every time.
With ascii encoding, this would limit me to 17 characters, but the alphanumeric encoding allowed up to 25 characters. Since DNS is case-insensitive, this let me carve a slightly longer URL. The only downside was that it required making a custom redirect on my own website, since I couldn’t find any url shorteners that would use all caps.
To this day, it is the most effort I’ve put into rick-rolling somebody.