App Start Instrumentation
Learn more about the Sentry App Start Instrumentation for the Flutter SDK.
Sentry's app start instrumentation provides insight into how long your application takes to launch.
App start instrumentation is available on iOS and Android.
Before diving into the configuration, it's important to understand how app start instrumentation behaves:
App start instrumentation tracks the duration between the earliest native process initialization and the first frame rendered (as reported by addTimingsCallback). Once the app start is processed, the callback is removed to avoid additional overhead.
When the SDK receives the start and end times of the app launch, the SDK:
- Creates a transaction named
ui.load - Attaches a span with either
app.start.coldorapp.start.warmoperation - Adds app start metrics to the transaction
Sentry's App Start instrumentation aims to be as comprehensive and representative of the user experience as possible, and adheres to guidelines by the platform vendors. For this reason, App Starts reported by Sentry might be longer than what you see in other tools.
Before starting, ensure:
This instrumentation is automatically enabled. There is no need for further configuration.
Launch your Sentry configured app.
Open the sentry.io performance page, find, and select the 'root /' transaction and navigate to the trace view of a sampled event.
Select the event within your transaction. Sentry displays the app start metrics on the right side of the screen in the Mobile Vitals section.
Our documentation is open source and available on GitHub. Your contributions are welcome, whether fixing a typo (drat!) or suggesting an update ("yeah, this would be better").