Kordant/tasks/ios-production/12-launch-time.md

12. App Launch Time Optimization

meta: id: ios-production-12 feature: ios-production priority: P2 depends_on: [] tags: [performance, launch, production]

objective:

• Optimize app launch time to under 2 seconds for cold starts and under 1 second for warm starts

deliverables:

• Launch time measurement and baseline
• Optimized app initialization
• Lazy loading of heavy components
• Reduced binary size

steps:

1. Measure current launch time:
   • Use Xcode Metrics Organizer
   • Use os_signpost for custom timing
   • Measure cold start (first launch after reboot)
   • Measure warm start (subsequent launches)
   • Establish baseline metrics
2. Optimize app delegate:
   • Minimize work in application(_:didFinishLaunchingWithOptions)
   • Defer non-critical initialization
   • Move heavy setup to background threads
   • Avoid blocking main thread
3. Lazy load heavy components:
   • Defer VoicePrint model loading until needed
   • Defer document scanner initialization
   • Lazy load WebView components
   • Load dashboard data after UI appears
4. Optimize storyboards/XIBs:
   • Remove unused storyboards
   • Minimize view controller initialization
   • Use code-based UI where faster
5. Reduce binary size:
   • Strip debug symbols from release builds
   • Remove unused resources and assets
   • Compress images in asset catalog
   • Enable dead code stripping
6. Optimize framework loading:
   • Link frameworks statically where possible
   • Reduce dynamic framework count
   • Prelink common frameworks
7. Add launch screen optimization:
   • Simple, static launch screen
   • Match first screen of app
   • No animations or complex layouts

tests:

• Performance: Measure launch time on iPhone 12
• Stress: Launch app 100 times, average time <2s
• Memory: No memory spikes during launch

acceptance_criteria:

• Cold launch time <2 seconds on iPhone 12
• Warm launch time <1 second on iPhone 12
• Launch screen visible for <500ms
• No blocking operations on main thread during launch
• Binary size <100MB (App Store limit is much higher)
• Heavy components loaded lazily after launch
• Launch time measured and tracked in CI
• No crashes during launch under memory pressure

validation:

• Xcode Metrics → cold start <2s, warm <1s
• Instruments Time Profiler → no long blocking calls on main thread
• Physical device test → feels instant
• App Store Connect → binary size acceptable

notes:

• Launch time is critical for App Store review and user retention
• iOS may terminate apps with launch times >20 seconds
• Use pre-warmed launches for more accurate measurement
• Test on oldest supported device (iPhone SE 2nd gen or similar)