[tronster]

I've only dabbled with QR codes but they are interesting. Do you have any links that go into more detail about uppercase making them smaller?

[the_mitsuhiko]

https://www.thonky.com/qr-code-tutorial/alphanumeric-mode-en...

[lifthrasiir]

In addition to mitsuhiko's link, there is even a dedicated binary-to-text encoding suitable for the alphanumeric mode of QR codes: https://datatracker.ietf.org/doc/html/rfc9285