I honestly don't see why you wouldn't consider SQLite to be a "proper database." I think it has a reasonably competitive feature set. In a usecase where you c

I honestly don't see why you wouldn't consider SQLite to be a "proper database." I think it has a reasonably competitive feature set. In a usecase where you consider independent databases, with few interactions between them, for millions of users (and a few MBs + binary blobs of data per user) I'd certainly consider it as a possible solution.