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)
import FirebaseCore
import FirebaseCrashlytics
@main
struct MyApp: App {
init() {
FirebaseApp.configure()
}
}
Non-fatal errors (track without crashing)
Crashlytics.crashlytics().record(error: error)
Crashlytics.crashlytics().setCustomValue(userId, forKey: "user_id")
Crashlytics.crashlytics().setCustomValue(screenName, forKey: "current_screen")
Android (Kotlin)
implementation("com.google.firebase:firebase-crashlytics:18.x.x")
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:
./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 piecerating-prompt-strategy — Recover rating after fixing crash-driven 1-starsreview-management — Respond to crash-related reviewsretention-optimization — Crashes on Day 1 destroy retention metricsapp-store-featured — Crash rate > 2% disqualifies editorial featuring
