Setting the file. One moment.
Subchapter 5.1
references/metrics.mdMarkdown3 KBView on GitHub
Quick reference for reading EAS Observe dashboards and CLI output.
Source: https://docs.expo.dev/eas/observe/reference/metrics/ — this is the canonical reference for metrics. Consult this page for the latest guidance, full prose definitions, optimization tips, and rationale.
All durations are in seconds. Data is retained for 90 days. All durations are in seconds. By default, every installation dispatches all of its events. Apps with high volumes can opt into per-installation sampling via configure({ sampleRate }). See Sampling (opens in a new tab).
| Metric | Full name | Target | Auto-collected? |
|---|---|---|---|
| Cold launch | expo.app_startup.cold_launch_time | < 1.5s | Yes (native-only — JS code does not affect it) |
| Warm launch | expo.app_startup.warm_launch_time | < 0.5s | Yes (OS decides when warm vs cold happens) |
| Bundle load | expo.app_startup.bundle_load_time | < 0.3s | Yes (JS load + evaluation, before runApplication) |
| Time to first render (TTR) | expo.app_startup.ttr | < 2s incl. cold launch | Yes when root is wrapped with AppMetricsRoot (SDK 55) / ObserveRoot (SDK 56+) |
| Time to interactive (TTI) | expo.app_startup.tti | < 3s incl. cold launch | No — call markInteractive() once the screen is genuinely usable |
Both TTR and TTI are measured from native launch through the React render, so the cold-launch portion counts against them.
Every TTI event carries three frame-rate params. The pattern of high/low values across them tells you what kind of slowness you’re seeing.
| Param | Definition | What it indicates |
|---|---|---|
expo.frameRate.slowFrames | Count of frames ≥ 17ms | Main thread consistently busy during launch (heavy layout, sync bridge calls, too many components rendering) |
expo.frameRate.frozenFrames | Count of frames ≥ 700ms | Hard freezes. Even one during startup is a serious issue (sync I/O, large JSON parsing, blocking network) |
expo.frameRate.totalDelay | Total accumulated time (seconds) frames exceeded their target duration | Best single “smoothness” number — compare to TTI |
Diagnostic patterns:
__DEV__ = true) do not dispatch metrics unless configure({ dispatchInDebug: true }) is set.environment tag (defaults to process.env.NODE_ENV) is metadata only — it does not gate dispatch by itself.Observe.dispatchEvents() is called.AppMetricsRoot / ObserveRoot, markInteractive): see ./setup.md../queries.md.