Android development. Is there any free services to synchronize user data?

The problem arose to provide users with the ability to synchronize data between devices.
Cloud storage type Azure, Amazon, Google, all paid. Is there a free equivalent?
It is not about the filesharing, and on data from DB, accordingly I would like to have something like a noSQL database on the other side.
July 2nd 19 at 17:10
3 answers
July 2nd 19 at 17:12
Solution
Is there a fully freestuff Cloud storage ?
Does he have a completely free Internet ? If not exactly dial-up ?
Does he have a completely free server ?
Is there a fully freestuff and eternal HDD\SSD ?
HDD 100 terabytes or exabytes 100500 ? Completely free, or only 98% ?
Does he have completely free electricity ?
Does he have completely free air conditioning and room rental ?
Does he have a fully free watchman and a cleaning lady ?

So is there a fully freestuff Cloud storage ?
July 2nd 19 at 17:14
Firebase can be used for free, we have not reached the limits.
July 2nd 19 at 17:16
Will not go. Firebase is more for the centralized distribution of messages to different clients.
And then every customer is your repository, and accordingly, each requires sufficient space (at least 1Gb).
Well, plus need some kind of transparent system of "registration" using this API DBaaS (if I correctly understand the terminology).
Something similar seemed to have OpenDrive, in any case, the API for the "seamless check in" there. But there are other limitations that I don't know. how to get around. It's not DBaaS, and of course, to build a sync problem there - not to download each time the horse amounts of information.

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