[bigfish24]

(Adam from Realm) First, we respect everything Firebase and team has done. Others might feel differently, but shipping great software is hard, so nothing but respect from us there.

Second, and to address your question, we are very different architecturally than Firebase. We built from the ground up an object database that runs on mobile. As a result, this means when using Realm Object Server, the mobile development is still focused around that database. In practice, this means developers only have to think about local APIs because their UI is now bound to the data in their local Realm, with the networking handled automatically. This isn't just a basic cache, though, but a full-featured database that includes: memory-mapped object interface, ACID compliance, querying, and much more. Firebase doesn't offer that capability since it's mobile SDKs aren't built off a mobile database like Realm.

Beyond the mobile capability/developer experience, the server-side capabilities of Realm Object Server go beyond whether it is self hosted or not. While not included in the developer edition, we offer server-side SDK support and event handling capabilities so that the server can integrate into existing infrastructure vs attempt to control how you build your backend.