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Author here, thanks for posting this and glad people enjoyed reading. I did some editing and added a conclusion that boring QR codes are a better choice for rea

Author here, thanks for posting this and glad people enjoyed reading. I did some editing and added a conclusion that boring QR codes are a better choice for real world use. Easier for users to understand and more reliable. These artistic designs are mostly just for fun. One part which I barely touched was how to mathematically "force" pixels in the error correction section. It's an extension of the ideas covered in https://research.swtch.com/qart https://research.swtch.com/qart but unfortunately I don't grasp it well enough to explain properly.

vrypan 1mo ago
Amazing post. Tangentially related: https://blog.vrypan.net/2026/07/07/where-is-qrdo/ https://blog.vrypan.net/2026/07/07/where-is-qrdo/ It's a "where is the QR" game, where a mobile is more capable in finding the pattern than a human.
- qqilihq 1mo ago
  Yes, detecting the QR code by eye can be really difficult like in this setting at QRocodile: https://qrocodile.io/en/?preset=morseCode&halo=background&step=pattern https://qrocodile.io/en/?preset=morseCode&halo=background&st... Hiding the code is maybe not good for getting scans but a nice idea for some kind games... can imagine this being a part of an "Escape Room" game :D
Walf 1mo ago
>Alphanumeric mode can encode URLs, but it only supports uppercase characters, so no one uses it. I found that they are still pretty useful because they're noticeably smaller grids. They can be enlarged to use up the same space on screen/print as a denser UTF-8 QR, thus be clearer and easier to scan. Some readers will assume that an all-uppercase URL is supposed to be lowercase and convert it, others will use them as-is. Use short URLs, like https://qr.test/thing https://qr.test/thing so only the case of the path part matters, then make sure /thing and /THING go to the same place, and you're good. Thanks for the informative guide.

vrypan 1mo ago

Amazing post. Tangentially related: https://blog.vrypan.net/2026/07/07/where-is-qrdo/ https://blog.vrypan.net/2026/07/07/where-is-qrdo/ It's a "where is the QR" game, where a mobile is more capable in finding the pattern than a human.

qqilihq 1mo ago
Yes, detecting the QR code by eye can be really difficult like in this setting at QRocodile: https://qrocodile.io/en/?preset=morseCode&halo=background&step=pattern https://qrocodile.io/en/?preset=morseCode&halo=background&st... Hiding the code is maybe not good for getting scans but a nice idea for some kind games... can imagine this being a part of an "Escape Room" game :D

Walf 1mo ago

>Alphanumeric mode can encode URLs, but it only supports uppercase characters, so no one uses it. I found that they are still pretty useful because they're noticeably smaller grids. They can be enlarged to use up the same space on screen/print as a denser UTF-8 QR, thus be clearer and easier to scan. Some readers will assume that an all-uppercase URL is supposed to be lowercase and convert it, others will use them as-is. Use short URLs, like https://qr.test/thing https://qr.test/thing so only the case of the path part matters, then make sure /thing and /THING go to the same place, and you're good. Thanks for the informative guide.