Mobile

Build mobile applications with proper lifecycle handling, offline support, and platform conventions.

Lifecycle Awareness

• App can be killed anytime in background—save state before backgrounding
• Restore state on return—user expects to continue where they left off
• Handle low memory warnings—release caches, non-essential resources
• Background tasks have time limits—complete or request extension

Permissions

• Ask in context, not at launch—explain why when requesting
• Degrade gracefully if denied—app should still work with reduced features
• Don't ask for unnecessary permissions—users notice and distrust
• Re-request after demonstrating value—not immediately after denial

Offline First

• Assume network is unreliable—design for offline, sync when possible
• Cache aggressively—previous content better than loading spinner
• Queue actions for retry—don't fail on network error
• Conflict resolution strategy—last write wins or manual merge
• Show sync status—user should know if data is current

Performance

• Target 60fps—dropped frames feel janky
• Main thread for UI only—heavy work on background threads
• Memory matters more than desktop—constrained devices, aggressive OS killing
• Battery awareness—reduce location polling, network requests when possible
• Startup time under 2 seconds—first impression matters

Navigation Patterns

• Follow platform conventions—iOS back gesture, Android back button
• Navigation stack manageable—don't go 10 levels deep
• Deep link to any screen—shareable, notification taps work
• Preserve scroll position on return—don't jump to top

Notifications

• Push for time-sensitive external events—new message, delivery update
• Local for reminders, timers—user-initiated
• Don't spam—users will disable; quality over quantity
• Actionable when possible—reply, mark done from notification
• Group related notifications—less intrusive

Deep Linking

• Universal Links (iOS) / App Links (Android) for owned domains
• Handle gracefully when app not installed—fallback to web
• Parse parameters safely—malicious links exist
• Test all entry points—not just main launch

Storage

• Secure storage for tokens, credentials—Keychain, Keystore
• User data survives reinstall where appropriate—cloud backup
• Cache is cache—can be cleared; don't store critical data
• Large files: consider on-demand download—not bundled in app

Input Handling

• Keyboard avoidance—content shifts to stay visible
• Dismiss keyboard appropriately—tap outside, scroll, submit
• Input accessories for relevant actions—next field, done, toolbar
• Paste, autofill support—reduce typing on small keyboards

Touch and Gestures

• 44pt minimum touch target—consistent with platform guidelines
• System gestures reserved—don't override swipe from edge
• Gesture discoverability—hint or teach, don't assume knowledge
• Haptic feedback for significant actions—confirmation, errors

Accessibility

• VoiceOver (iOS) / TalkBack (Android) testing—navigate entire app
• Dynamic type support—text scales with user preference
• Sufficient contrast—check in accessibility inspector
• Labels on all interactive elements—not just visible text

Testing

• Real devices essential—simulators miss performance, sensors, edge cases
• Multiple OS versions—support at least current minus 2
• Different screen sizes—small phones to tablets
• Network conditions—slow, intermittent, offline

App Store Survival

• Read rejection reasons before submitting—common pitfalls documented
• Privacy policy required—explain data collection
• Login test account for reviewers—if auth required
• No placeholder content—everything functional in review build
• Update regularly—abandoned apps get deprioritized