When I think of street food in Germany, I think of sausages grilling in street stalls. All manner of sausages...rindwurst, brockwurst, currywurst - an institution in Germany...a sausage, sliced, with a mild curry gravy.
And being available everywhere, it must be terribly competitive...though I think there are probably one or two large industrialized suppliers to all the street vendors.
I had one as a sample by the Christmas Market at the Hamburg Rathaus.
But unsurprisingly, they are all very good, and almost the same.
This was cooked just right. The skin was springy, had a tough-ish consistency and the inside was nice and firm. The meat tasted very good, the smoky flavours imparted by the charcoal grill added to the flavour. I found the yellow mustard a bit weak, but I guess the German palate is more delicate than my fire breathing, chilli eating one...so acceptable.
Available almost everywhere in Germany.