The Moccaklatsch is THE place to eat for vegan people in Bielefeld. Every dip is based on a vegan mayonnaise, they serve a great vegan burger, a variety of vegan tapas, lentil curry, dumplings, vegan cakes, coctails and all kinds of coffee-drinks with soy milk (by the way the best coffee in town).
Everything is homemade and they have a changing menu of the day, even with different vegan desserts. All this in a really great atmosphere in the center of Bielefeld.
Big groups should reserve a table.
Cons: Not the cheapest place, Not fully vegetarian, serves meat