I'm new to this, but it seems to be that the least painful way to write an "offline first" social network app would be to use a auto-synching database like Google "Cloud Firestore" or Realm Object Server because I believe it would greatly reduce the amount of server-side REST or GraphQL programming.

The client-side React Native code would just be driven by local objects that would auto-persist to the cloud.

(BTW, apparently Realm is prohibitively expensive: A salesperson wrote me and reported that Realm Object Server [self-hosted, no less...] costs over $2,000 for 500 users... so getting to 100K would bankrupt me!)

Any feedback? What would YOU use? What is the current state-of-the-art or best practice? Seems every app developer immediately hits this architecture issue and has to pick something!

Requirements (most important to least important)

• reliable
• massive scalability (10K, 100K?, 1M?? simultaneous users)
• lowest possible per user cost (no corporate license)
• client: "offline-first" use without Internet connection
• least amount of database-related code / boilerplate
• client: official React Native support
• technology we already know / are comfortable with
• client: query speed
• least amount of vendor "lock in" (easy to switch)
• open source (vs. black box)
• server: business logic & hooks
• server: daemon / scheduled task support
• transaction support
• ease of schema migration over time
• easily understood / not overly complex
• most current "popular tech" (what are the cool kids using?)
• client: JavaScript only (no native library required)
• self-documenting (generate documentation)