QR Code Generator (by Peter Minne) is an app (or website) that allows users to generate customized QR codes. It offers a wide range of features and settings that allow users to customize their QR codes to suit their needs. Users can choose from a variety of colors, shapes, and sizes, as well as add text, logos, and images to their QR codes. They can also add tracking features so that they can monitor and analyze the activity of their QR codes. In addition, users can also choose to generate static or dynamic QR codes, as well as lock their codes from being scanned by anyone other than the intended recipient. Finally, the app also allows users to save and share their QR codes with ease.
Discontinued is not compatible with newer versions of Firefox, etc.: https://addons.mozilla.org/en-US/firefox/addon/OfflineQR/