We are trying to answer this with CloudTables (https://cloudtables.com) - which is effectively a GUI for my DataTables library with a Postgres backend. Current work is to address the row limit and allow millions of rows without needing to contact "sales" (me), while also not charging per user (I hate that as a customer). If anyone fancies giving it a go and dropping me some feedback that would be most welcome! There are some rough edges without question that are still being worked on, but I think it has some advantages such as being able to self host with your own Postgres instance.