Mobile App Architecture
Mobile apps operate under constraints that web applications rarely face. Batteries drain, networks disappear, storage fills up, and operating systems kill background processes. Good mobile architecture anticipates these challenges rather than fighting them.
Mobile Constraints
Battery life affects every architectural decision. Constant network requests, GPS usage, and background processing drain batteries quickly. Users notice and uninstall power-hungry apps.
Variable networks range from fast Wi-Fi to slow cellular to no connection at all. Apps that assume constant connectivity frustrate users in elevators, subways, and rural areas.
Limited storage matters more on mobile than desktop. Users with full phones will delete apps to free space. Efficient data storage and cleanup policies help retention.
Background restrictions prevent apps from running freely when not in focus. iOS and Android aggressively limit background execution to save battery. You can't assume your code runs continuously.
Architecture Patterns
Mobile apps commonly use patterns that separate concerns clearly:
MVC (Model-View-Controller) divides data, presentation, and logic. It's simple but can lead to massive controller classes.
MVVM (Model-View-ViewModel) adds a ViewModel layer that prepares data for display. Popular in iOS (with SwiftUI) and Android (with Jetpack).
MVI (Model-View-Intent) uses unidirectional data flow. State changes flow in one direction, making behavior predictable and debugging easier.
Clean Architecture organizes code in layers with strict dependency rules. Business logic stays independent of UI frameworks and databases, making testing easier.
Designing for Offline
The best mobile apps work offline. An "offline-first" approach treats network as an enhancement rather than a requirement:
- Check local cache first
- Display cached data immediately
- Fetch updates from network in background
- Update cache with new data
- Refresh UI when updates arrive
- Handle conflicts when offline changes sync
This pattern keeps apps responsive regardless of network conditions. Users see content instantly while fresh data loads.
Conflict resolution — when offline edits clash with server changes — requires careful design. Simple strategies include "last write wins" or showing users both versions to choose.