Mobile App Caching Strategies: Boost Performance and Reduce Data Usage

Caching Fundamentals

Caching stores frequently accessed data for faster retrieval. Benefits include reduced network requests, faster app performance, lower data usage, and offline functionality. Implement multi-level caching: memory cache (fast, limited), disk cache (slower, larger), and network (slowest, always fresh). Cache appropriately based on data freshness requirements.

HTTP Caching

Leverage HTTP caching headers: Cache-Control (max-age, no-cache), ETag (conditional requests), Last-Modified (timestamp-based validation). URLSession (iOS) and OkHttp (Android) handle HTTP caching automatically. Configure cache size limits and implement cache policies (return cached data while revalidating for stale-while-revalidate pattern).

Proper HTTP caching can reduce network traffic by 70% and improve app responsiveness by 3x.

In-Memory Caching

Use NSCache (iOS) or LruCache (Android) for in-memory caching. These automatically evict items under memory pressure. Cache parsed objects, not raw data, set cost limits based on object size, and clear cache on memory warnings. In-memory cache is perfect for images, API responses, and computed values.

Disk Caching

Persist data to disk for longer-term caching. Use FileManager (iOS) or Context.getCacheDir (Android) for cache directory. Implement expiration policies, compress data before storing, use background threads for disk I/O, and respect system cache clearing. Popular libraries: Kingfisher (iOS), Glide (Android) for image caching.

Cache Invalidation

Cache invalidation is notoriously difficult. Strategies include: time-based expiration (TTL), version-based (cache key includes version), event-based (invalidate on user action), and manual refresh (pull-to-refresh). Implement cache warming for critical data and stale-while-revalidate for better UX.

Offline-First Architecture

Design apps to work offline by default. Cache all viewed content, queue mutations for later sync, show cached data immediately while fetching updates, and indicate staleness to users. Offline-first apps provide superior UX on unreliable networks and reduce server load.

Cache Size Management

Monitor and limit cache size to avoid filling device storage. Set maximum cache size (50-200MB typical), implement LRU eviction, provide cache clearing in settings, and respect system storage warnings. Users uninstall apps that consume excessive storage.