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Mobile Crash Reporting

When the mobile app crashes (JS error OR native Java/ObjC), we want to know — without depending on user reports.

Tools wired​

Sentry React Native (@sentry/react-native v8.8.0)​

  • Init in mobile/app/_layout.tsx reads EXPO_PUBLIC_SENTRY_DSN
  • No-op safe: empty DSN = silently disabled, app behaves identically
  • Captures: unhandled JS errors, unhandled promise rejections, native crashes (Java/ObjC), explicit Sentry.captureException() calls
  • Strips PII from request body, cookies before send
  • 10% performance trace sampling (tracesSampleRate: 0.1)

React ErrorBoundary​

  • Class component in _layout.tsx catches React render errors
  • Forwards to Sentry via Sentry.captureException() with the componentStack as context
  • Shows a "Something went wrong" screen with stack trace + "Try Again" button (only in dev / first-launch — production users get a cleaner screen)

Setup (when you're ready to enable)​

  1. Create Sentry project at sentry.io, platform = React Native, project name ka26-mobile
  2. Copy DSN from setup screen
  3. Add to mobile/app.json under extra: 
    {
      "expo": {
        "extra": {
          "EXPO_PUBLIC_SENTRY_DSN": "https://xxx@oXXX.ingest.sentry.io/YYY"
        }
      }
    }
  4. Rebuild APK — Sentry boots on next launch

What you'll see in Sentry​

  • Issues feed — every JS error grouped by stack trace
  • Performance — slow transactions (rare for mobile)
  • Release health — crash-free user % per release (target 99.5%+)
  • Breadcrumbs — last 100 actions before the error (taps, navigation, fetches)

Alerting​

Default Sentry alert: any new error type (never seen before) triggers an email. Configure on the project's Alerts page.

What NOT to forward to Sentry​

  • Routine 4xx errors that we threw on purpose (Authentication required, Rate limit exceeded) — these are filtered out via ignoreErrors config
  • Network blips (Network request failed, AbortError) — filtered, too noisy

Local crash debug (when no Sentry)​

  • iOS: Xcode → Devices and Simulators → device logs
  • Android: adb logcat -s ReactNative:V ReactNativeJS:V
  • Expo Dev Menu (shake the device): "Show Performance Monitor" + "Debug Remote JS"