App Startup Instrumentation

Generates: Spans

Measures cold launch duration from SDK initialization to the moment the first screen appears.

How It Works

When Pulse.shared.initialize(...) is called, the SDK records a start timestamp. When the first UIViewController.viewDidAppear fires, the startup span is closed. The resulting span (AppStart) captures exactly how long it took for the user to see the first usable screen.

Configuration

App startup tracking is enabled by default.

Pulse.shared.initialize(
    endpointBaseUrl: "https://your-backend.com",
    apiKey: "your-api-key",
    instrumentations: { config in
        config.appStartup { $0.enabled(true) }  // default: true
    }
)

Generated Telemetry

Type: Span
Span Name: AppStart
Span Kind: Internal
pulse.type: app_startup

Attributes

Attribute	Description	Example	Always Present
pulse.type	Instrumentation type	"app_startup"	✅ Yes
screen.name	First screen that appeared	"HomeViewController"	✅ Yes
session.id	Session identifier	"f40364c92b85ec0c19c35a65be42b97f"	✅ Yes

Sample Payload

{
  "name": "AppStart",
  "kind": "INTERNAL",
  "duration_ms": 843,
  "attributes": {
    "pulse.type": "app_startup",
    "screen.name": "HomeViewController",
    "session.id": "f40364c92b85ec0c19c35a65be42b97f"
  }
}

Best Practices

• Initialize the SDK as early as possible — in application(_:didFinishLaunchingWithOptions:) or the App init() — to capture the full cold launch duration.
• The startup span only fires once per process. Subsequent viewDidAppear calls after the first are tracked by Screen Lifecycle instrumentation.

Disabling App Startup

config.appStartup { $0.enabled(false) }