Using Box as a repository for an application

Hello all,

My team and I have some questions around the API features offered by BOX.

Currently, we are thinking to build an application where the end users can upload documents (pdf/photos, etc.) to our app and Box will be the storage.

We are planning something like this below.

End users（approx. 1000 users）>>> App using DBX platform>>> (The App accesses BOX on behalf of all end users and takes actions on each user's folders and files via API）>>> Box

I know that each business plan has a limit for API call.

However, BOX platform seems to be only included in the enterprise plan.

If I want to do something on what I describe above, do I need an enterprise plan account.

In any case, how many license do I need to build something described above?

I assume one license is enough if we have the credential set up in the server side of the application with a proper authentication mechanism.

Does anyone have done something similar? Is this use case rare?