thanks for your reply 
What webinterface do you mean? In soundcloud.com i can see me playlist. In mopidy i dont see the playlists. If i use the javacript class du query the existing playlist only the spotify one shows up. But the search is working in soundcloud, too. I get result from soundcloud and can play them.
In mopidy-soundcloud github i cant see any playlist provider and any “as_list” function. This is required to show playlists from the backend in mopidy, isnt it?
If this is the issue i will try to implement it already checked the Soundcloud api and mopidy-soundcloud source code.