Mobile Backend and APIs
Most mobile apps require backend services for data storage, user authentication, push notifications, and business logic. Understanding backend integration is essential for building complete mobile solutions.
REST APIs
REST (Representational State Transfer) APIs communicate over HTTP using JSON. Methods: GET (read), POST (create), PUT (update), DELETE (remove). Mobile apps consume REST APIs using HTTP client libraries (Retrofit, URLSession). API design should be versioned, documented, and secured.
Firebase
Firebase (Google) provides backend-as-a-service: Authentication (email, Google, Facebook login), Firestore (NoSQL database with real-time sync), Cloud Storage (files), Cloud Messaging (push notifications), Analytics, Crashlytics, and Remote Config. Firebase accelerates development.
Authentication
User authentication methods: email/password, social login (OAuth with Google, Facebook, Apple), phone number (OTP), and biometrics (fingerprint, face). JWT (JSON Web Tokens) manage sessions. Secure token storage is critical for mobile security.
Push Notifications
Push notifications engage users when the app is not active. FCM (Firebase Cloud Messaging) for Android, APNs (Apple Push Notification service) for iOS. Notifications can be triggered by backend events, scheduled, or targeted by user segments. Overuse causes users to disable notifications.
Offline Support
Mobile apps should handle poor or no connectivity gracefully. Strategies: local database caching, queue pending operations, sync when online, show cached data with staleness indicators. Room (Android) and Core Data (iOS) provide local persistence with sync capabilities.
Cloud Services
Beyond Firebase: AWS Amplify (Amazon), Azure Mobile Apps (Microsoft), Supabase (open-source Firebase alternative). These provide databases, authentication, storage, serverless functions, and APIs. Choice depends on existing infrastructure and requirements.
Summary
Mobile backends provide essential services: APIs, authentication, push notifications, and offline support. Firebase and cloud platforms accelerate development while REST APIs enable custom backend integration.