RUM Overview
The Overview tab is your health-at-a-glance dashboard for the selected mobile application, combining top-line stats, trend charts, breakdowns by app version/OS/device, and the screens most worth investigating.
Key Metrics
| Metric | Description |
|---|---|
| Crash-Free Sessions | Percentage of sessions with no crashes |
| Total Sessions | Number of user sessions in the range |
| Active Users | Distinct users in the range |
| Avg Cold Start | Average cold app-startup time, with a trend sparkline |
| Avg Warm Start | Average warm app-startup time, with a trend sparkline |
| Total Errors | Count of reported non-fatal errors |
Use the shared Filters sidebar (Device, App, Session, Network) to scope every metric below to a specific slice of traffic.
Total Sessions reflects the app's configured session sample rate (the SDK defaults to sampling 1% of sessions). Crash-Free Sessions and Total Errors aren't affected by that sampling - crash, error, and ANR telemetry bypasses the session sample rate by default, so those counts stay accurate even at a low sample rate. See Sessions in the instrumentation guide for how sampling is configured.
Trends Over Time
Three daily time-series charts sit right under the Key Metrics row:
Sessions Over Time
Session volume per day. Use it to spot release-day spikes or a sudden drop in traffic that might indicate an app outage or a broken build.
Crashes Over Time
Crash volume per day. A spike here that lines up with a Sessions spike usually means a release just went out; check Crashes for which crash groups are driving it.
ANR Duration Over Time
Frozen-UI (ANR) duration per day. Sustained increases point at a regression in a specific screen or build; cross-check against ANR for the affected screens.
Detailed Breakdown
Expand Detailed Breakdown to slice Crashes, Sessions, and ANR Duration each three ways: by App Version, by OS Version, and by Device Model. Every chart pairs a multi-line time series with a table of Name / Min / Mean / Max, so you can see both the trend and the worst-case value per version, OS, or device at a glance:
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Crashes by App Version / by OS Version / by Device Model
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Sessions by App Version / by OS Version / by Device Model
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ANR Duration by App Version / by OS Version / by Device Model
This is the fastest way to answer "did the new release make things worse?" - compare the latest app version's line against previous versions in the same chart.
Top Screens
Two tables at the bottom of the Overview surface the screens most worth attention:
Top Crashing Screens
Columns: Screen, Crashes, Last Seen. Ranked by crash count over the selected range.
Slowest Screens
Columns: Screen, Avg Load, Views. Ranked by average load time.
Click through to Screens for the full per-screen breakdown, including frame timing and jank.
Use Cases
Morning Health Check
- Check Crash-Free Sessions and Total Errors against their usual range
- Scan Sessions Over Time and Crashes Over Time for overnight anomalies
- Glance at Top Crashing Screens for anything new
Post-Release Monitoring
- Filter by the new App Version in the Filters sidebar
- Compare its line in the Crashes by App Version and ANR Duration by App Version breakdowns against the previous version
- If crashes or ANR duration are elevated, jump to Crashes or ANR to find the specific cause
Investigating a Spike
- Find the spike in Crashes Over Time or ANR Duration Over Time
- Narrow the time picker to that window
- Check Top Crashing Screens for the screen driving it, then open Crashes or Screens for details
Related Guides
- Getting Started - Interface layout and shared filters
- Crashes - Crash groups and symbolicated stack traces
- Sessions - Session list and event timelines
- Users - Per-user activity and history