I have made a mobile app that is basically a mp3 player. The app is monetized: users can buy audio packs or subscribe (this is optional).
However in addition to buying audio packs they can also use their own files for free.
I want to allow them to also search the Freesound library directly from the app using the API and download the sounds directly into the app. This would not be a paid feature or behind a subscription, it's just something that I think would be super useful for the users.
So to my question: is this usage non-commercial or do I need to somehow license it?
Thanks.