@sundogplanets Here are three unencumbered (and open source) tools that I regularly use:

Web-based one, provided by @Framasoft :
https://omnitools.framatoolbox.org/image-generic/qr-code

Android application:
https://f-droid.org/en/packages/com.atharok.barcodescanner/

Linux command line (available in most distros packages directly):
https://github.com/fukuchi/libqrencode