Choosing a Backend for Your Mobile App: The 2025 Guide

Mobile apps have backend needs that web apps don't: offline persistence (data must sync when connectivity returns), push notifications, binary data handling (photos, videos from cameras), device-specific auth (biometrics, Apple/Google sign-in), battery-efficient background sync, and App Store compliance for data handling and privacy.

Firebase has been the default mobile backend for years. Its mobile SDKs (iOS, Android, Flutter) are excellent with built-in offline persistence, real-time sync, and push notifications (FCM).

Firebase is right if your app is mobile-only, needs real-time sync, requires offline-first architecture, and you're comfortable with NoSQL. Downsides: proprietary lock-in, NoSQL limitations, unpredictable pricing at scale.

Best for: Chat apps, social apps, collaborative tools — anything where real-time sync is critical.

Supabase is gaining traction with React Native and Flutter developers who prefer SQL databases. Its real-time subscriptions and auth integrate well with mobile frameworks. Growing client libraries for Dart (Flutter), Swift, and Kotlin.

Advantages: PostgreSQL, row-level security, relational data. Downsides: offline persistence isn't as mature as Firebase's, mobile SDKs are newer.

Best for: Mobile apps with relational data, apps sharing a backend with web, teams that prefer SQL.

ShipStack's REST API works identically across all mobile platforms. A fetch() in React Native, http in Flutter, URLSession in Swift, and Retrofit in Kotlin all hit the same endpoints and get the same JSON responses.

Unique advantage: if you build for both iOS and Android, your data layer code is identical. No platform-specific SDK behavior to debug.

Best for: Cross-platform apps, agencies building mobile apps for clients, teams wanting provider flexibility.

Offline support is the hardest mobile backend problem.

Firebase approach: Firestore's built-in offline persistence caches data locally and syncs when online. Easiest path but locks you into Firestore.

REST API approach: Implement client-side caching with SQLite as the primary store. Sync to the server when online using a queue-based approach: write operations go to a local queue, a background process sends queued operations when online, handle conflicts with last-write-wins.

Libraries like WatermelonDB (React Native) and Drift (Flutter) simplify this pattern.

For most mobile apps in 2025:

1. Use ShipStack as your API layer for auth, database, and storage. 2. Use Supabase as your provider (PostgreSQL for relational data). 3. Add local caching with SQLite for offline support. 4. Use Firebase Cloud Messaging for push notifications (works regardless of backend). 5. Keep your data layer in a separate module shared between platforms.

This gives you the flexibility to serve iOS, Android, and web from a single backend while keeping options open for provider changes.