Sync SQLite database in real time

I have apps for Android and iOS which store data in local SQLite databases. App works completely offline with no syncing among the devices.

Now, I wish to have two things:

1. Sync these SQLite databases among various Android and iOS devices. Changes on one device shall be reflected in real time on another device.
2. Have a web based version of my app where the user can login and access his data. The changes to this data shall then be reflected in real time on his mobile devices as well.

So, a sync required among web based data and mobile SQLite database as well.

I think I need to setup a MySQL (or any other) database (server-side) which shall sync in real time with SQLite database (on mobiles)

I went through Parse, Firebase but they seem to be JSON based (NoSQL). Then I saw AWS and got confused.

Anyone can guide me in the right direction? Which service would solve my problem? Which one would be efficient and easy to implement?