crash-analytics

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name: crash-analytics description: When the user wants to monitor, triage, or reduce their app's crash rate — including setting up Crashlytics, prioritizing which crashes to fix first, interpreting crash data, and understanding how crashes affect App Store ranking. Use when the user mentions "crash", "crashlytics", "crash rate", "ANR", "app not responding", "crash-free sessions", "crash-free users", "symbolication", "stability", "firebase crashes", "app crashing", or "crash report". For overall analytics setup, see app-analytics. metadata: version: 1.0.0

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

1. Sort by "Impact" (unique users affected), not frequency
2. Group: onboarding, checkout, core feature, background, launch
3. Assign P0/P1 to the top 3–5 issues
4. 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:

1. Open the file and line in Xcode (UserProfileVC.swift:87)
2. Check what can be nil at that point
3. Reproduce with the user context (OS version, device, screen)
4. 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

1. Identify the app version where crash-related 1-stars appeared
2. Fix the crash
3. Reply to each crash-related review: "Fixed in version X.X — please update"
4. 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

Related Skills

• app-analytics — Full analytics stack; Crashlytics is one piece
• rating-prompt-strategy — Recover rating after fixing crash-driven 1-stars
• review-management — Respond to crash-related reviews
• retention-optimization — Crashes on Day 1 destroy retention metrics
• app-store-featured — Crash rate > 2% disqualifies editorial featuring