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

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