I'm building a invoice app for iOS. I need a way to sync data between several devices of the same company that use the app. This have the common customers, product, inventory, invoices/detail tables.
I wonder if firebase is suitable for this.
Mainly, my main concern is that some iOS devices need to operate disconnected for some time (up to 1 day, people work in locations with poor or non-existent communication).
My second concern is for some customers that could use it as POS, and generate large amounts of invoices, to the same company group. My app is used for small supermarkets and wholesale distributors, that is the reason some travel and some stay in a local.
For the look of it, I think firebase is the closer solution for this (I'm considering pusher, parse and pubnub) because have a copy of the data and become the "database master" of this.
I have think in have a central postgress database as the database master, but maybe unnecesary with firebase?