That is correct. The only "problem" is that the model has no idea what these entities are. It doesn't care. Right now your recommendations might include both users and items. That might be useful! but usually it's not. Something has to filter them. So, that also means you need a way to distinguish user and item IDs.    You can filter them on the caller side. Just ignore values you don't like and go back and ask for more recs if there are not enough.   Or you can use RescorerProvider to inject the filtering logic onto the server side. That can be faster but is more work. ... View more