What is open on a Sunday in Rothenburg ob der Tauber in Germany?

Besides the touristic attractions there will be open restaurants / cafés and souvenir shops. Every other shop has to be closed by law. Of course, mini-shops in filling stations will be open.

If you are just the normal tourist, wanting to visit a restaurant, see some shops, etc, I don't think you will be too much inconveniences by it being Sunday. if you are staying in an apartment and need to buy food, too bad.

Food is always available at the Hbf and the Ost Bahnhof, even on Sunday. Now I noticed this is for Rothenburg. My comment applies to Munich. Lee is correct as usual- buy your apartment food at the REWE on Saturday...