[xaduha]

There's also http://www.28.io (totally ungooglable name, btw. Also know as "28msec").

http://www.28.io/documentation/latest/data-sources/

Not really comparable to Parse, even though they call it "Virtual Databases". Sure, you can query everything, but what about updates?

EDIT: Looks like they have updates, but I couldn't find whether they support similar uniform interface to updates as they have for queries (ideally XQuery Update Facility).

http://www.28.io/documentation/latest/modules/connectors