Not sure about now, but last year your only way of getting a digital vignette for the Austrian highway that is valid “today” was via a third party (from outside Austria, I think).

Austrian ASFINAG would only sell you one that is valid in ~2 week at the earliest, since that’s the time you are guaranteed by law to return it. Not very handy if you are already on the road, and don’t want to stop to buy a physical vignette.

Sorry, should have specified that I'm looking for examples for Germany, as this was what the parent comment was talking about.