CS50's QR Code Generator is a web app at cs50.codes via which anyone can generate, from URLs, long-lasting QR codes, which can be copied to your clipboard or downloaded as a PNG. The URLs are encoded in the QR codes themselves; they're not HTTP-redirected through CS50's own servers.
CS50's QR Code Generator supports, via GET, these HTTP parameters:
url, the value of which is a URL to be encodedlevel, the value of which, if present, must beL,M,Q, orHper wikipedia.org/wiki/QR_code#Error_correction, the default value of which isH
A request (with a URL like https://www.youtube.com/watch?v=oHg5SJYRHA0) can be submitted via cURL with
curl -J -O "https://cs50.codes/?url=https://www.youtube.com/watch?v%3DoHg5SJYRHA0"
which will save the QR code as qr.png.
The QR code can also be embedded with HTML like:
<img alt="QR code" src="https://cs50.codes/?url=https://www.youtube.com/watch?v%3DoHg5SJYRHA0">
Special thanks to lincolnloop/python-qrcode for its pure python QR Code generator!