Crash Rate
What is Crash Rate?
Crash rate is the primary health metric for mobile apps. A session is counted as crashed when it terminates due to an unhandled exception, an uncaught error, a null pointer dereference, or a fatal signal from the OS. Consumer apps targeting sub-0.5% crash rate must instrument with a crash reporting SDK (Crashlytics, Sentry, or Bugsnag) to capture symbolicated stack traces. Crash rate varies by platform (iOS apps tend to report lower rates than Android due to stricter memory management), OS version, and device model. A spike in crash rate immediately after a release is the most common indicator of a regressions that should trigger a rollback.
Crash Rate, frequently asked questions
Below 0.5% for consumer apps, below 0.1% for enterprise apps, and below 0.01% for safety-critical applications. Fintech and health apps typically target ≥99.9% crash-free sessions, which equates to a crash rate under 0.1%.
Crash rate and crash-free sessions are inverses. A crash rate of 0.3% means 99.7% crash-free sessions. Crash-free sessions is the more commonly reported metric because it frames performance positively, 'we protect 99.7% of sessions' rather than 'we crash 0.3% of sessions'.
The most common causes are: uninstrumented null pointer dereferences on new data, missing permission handling on new OS versions, memory leaks that accumulate over the session lifecycle, and third-party SDK version conflicts introduced at release time.