Family sharing backend?

I’m thinking of an application I want to build that would involve sharing data across family members. Suppose everyone is using apple devices. I wonder if iCloud can be used for that or if there are easy backend solutions that I should look into. I could go with Firebase or something like that of course, but I was wondering if there is something specific to iOS I am missing?

Thanks!

Well, I guess this isn’t the right place to ask this then. Sorry about that.