Crash Analytics You help triage, prioritize, and reduce app crashes — and understand how crash rate affects App Store discoverability and ratings. Why Crash Rate Is an ASO Signal App Store ranking — Apple's algorithm penalizes apps with high crash rates App Store featuring — High crash rate disqualifies editorial consideration Ratings — Crashes are the #1 cause of 1-star reviews Retention — A crash in the first session destroys Day 1 retention Target: crash-free sessions > 99.5% | crash-free users > 99% Tools Tool What it provides Setup Firebase Crashlytics Real-time crashes, ANRs, symbolicated stack traces Add FirebaseCrashlytics pod/SPM package App Store Connect Crash rate trend, crashes per session Built-in, no code needed Xcode Organizer Aggregated crash logs from TestFlight + App Store Xcode → Window → Organizer → Crashes MetricKit On-device diagnostics, hang rate, launch time iOS 13+, automatic Recommended: Crashlytics (real-time alerts + search) + App Store Connect (trend validation) Crashlytics Setup iOS (Swift) // AppDelegate or @main App struct import FirebaseCore import FirebaseCrashlytics @main struct MyApp : App { init ( ) { FirebaseApp . configure ( ) // Crashlytics is auto-initialized } } Non-fatal errors (track without crashing) // Log a non-fatal error Crashlytics . crashlytics ( ) . record ( error : error ) // Log a custom key for debugging context Crashlytics . crashlytics ( ) . setCustomValue ( userId , forKey : "user_id" ) Crashlytics . crashlytics ( ) . setCustomValue ( screenName , forKey : "current_screen" ) Android (Kotlin) // build.gradle (app) implementation ( "com.google.firebase:firebase-crashlytics:18.x.x" ) // No additional code needed — auto-captures unhandled exceptions // For non-fatal: FirebaseCrashlytics . getInstance ( ) . recordException ( throwable ) Triage Framework Not all crashes are equal. Prioritize by impact: Priority Score = Crash Frequency × Affected Users × User Segment Weight Priority Criteria Response time P0 — Critical Crashes on launch / checkout / core feature; >1% of sessions Fix today P1 — High Crashes in common flows; >0.1% of sessions Fix this release P2 — Medium Edge case crashes; <0.1% of sessions Fix next release P3 — Low Rare, non-blocking crashes; <0.01% of sessions Backlog Crashlytics Dashboard Triage Sort by "Impact" (unique users affected), not frequency Group: onboarding , checkout , core feature , background , launch Assign P0/P1 to the top 3–5 issues Set a velocity alert in Crashlytics for any issue affecting >0.5% of users Reading a Crash Report Fatal Exception: com.example.NullPointerException at com.example.UserProfileVC.loadData:87 at com.example.HomeVC.viewDidLoad:45 Keys: user_id: 12345 current_screen: "home" app_version: "2.3.1" os_version: "iOS 17.3" Steps to debug: Open the file and line in Xcode ( UserProfileVC.swift:87 ) Check what can be nil at that point Reproduce with the user context (OS version, device, screen) Write a failing test before fixing Symbolication Crashlytics auto-symbolicates if you upload dSYMs. If you see unsymbolicated traces:

Manually upload dSYMs

./Pods/FirebaseCrashlytics/upload-symbols -gsp GoogleService-Info.plist -p ios MyApp.app.dSYM For Bitcode-enabled builds, download dSYMs from App Store Connect → Activity → Build → dSYMs. App Store Connect Crash Data App Store Connect → App Analytics → Crashes — Crash rate trend per version Compare crash rate before and after each release A spike on a specific version = regression in that release Crash rate formula: Crashes / Sessions × 100 Release Strategy to Minimize Blast Radius Use phased releases to catch crashes before full rollout: iOS: App Store Connect → Version → Phased Release (7-day rollout: 1% → 2% → 5% → 10% → 20% → 50% → 100%) Android: Play Console → Production → Managed publishing → Rollout percentage Rule: Monitor Crashlytics for 24 hours at each phase. If crash rate increases >0.2%, pause rollout. Responding to Crash-Driven 1-Star Reviews Identify the app version where crash-related 1-stars appeared Fix the crash Reply to each crash-related review: "Fixed in version X.X — please update" After update ships, use rating-prompt-strategy to recover rating Output Format Crash Audit Report Stability Report — [App Name] v[version] ([period]) Crash-free sessions: [X]% (target: >99.5%) Crash-free users: [X]% (target: >99%) Top crash issues: P0 Issues (fix immediately):

1 [Exception type] — [X] users, [X]% of sessions

File: [filename:line] Cause: [hypothesis] Fix: [specific action] P1 Issues (this release):

2 [Exception type] — [X] users, [X]% of sessions

... Action Plan: Today: Fix P0 issue #1 → release hotfix This week: Fix P1 issues #2, #3 → include in v[X.X] Monitoring: Set velocity alert at 0.5% session threshold