Every second counts when users are waiting for your app to load, and the difference between a successful launch and a slow startup can mean the difference between user retention and immediate deletion.
Slow startup times can lead users to abandon the app before they even see its value. When your app takes too long to initialize, users experience a frustrating delay before seeing the first usable screen.
This isn't just an inconvenience, it directly impacts your app's user retention.
Most performance issues arise from blocking operations running on the main thread during startup. These heavy tasks create bottlenecks that prevent your app from becoming quickly interactive. It's like trying to start a car while someone's holding down the brake, no matter how powerful the engine, you're going nowhere fast.
To illustrate how startup delays impact user experience and how such issues can be diagnosed, we intentionally introduced a 1-second delay in an app's initialization process.
We used the Now in Android app, the reference app example designed by the Google team and built with Kotlin and Jetpack Compose. In this experiment, we are using the Koin version of the Now in Android app and the Kotzilla SDK
The Kotzilla SDK integrates into any Kotlin application, using Koin’s container to gather essential data required to identify performance bottlenecks and other issues. It starts tracking performance from the initialization of Koin, providing insights into delays during and after this stage of the startup process.
Below is the code snippet demonstrating this setup:👇
class NiaApplication : Application(), ImageLoaderFactory { val imageLoader: ImageLoader by inject() val profileVerifierLogger: ProfileVerifierLogger by inject() override fun onCreate() { super.onCreate() // Start Kotzilla SDK KotzillaSDK.setup(this) // Start Koin with Kotzilla Analytics startKoin { androidContext(this @NiaApplication) analyticsLogger(AndroidLogger(DEBUG)) modules(appModule) workManagerFactory() } // Simulate a blockage on the main thread Thread.sleep(1000) ... }
A complete step-by-step guide to simulate this issue in the Now In Android app is available here if you'd like to try it for yourself.
We logged in to the Kotzilla Platform and clicked on the Dashboard button next to our app to access the app Dashboard View.
Then, we clicked on the Sessions View to visualize the list of recorded user sessions. In this example, we created three user sessions with the same interactions to see if there were any significant differences among the three runs:
Notice that the Max Event Duration column for these sessions does not reflect the 1-second delay we introduced in the initialization process. This is because the delay occurs during the app's initialization phase, specifically before the first screen is loaded or any user interaction is recorded.
The platform's detailed timeline view 👇 allows you to closely examine each specific user session. You're then able to clearly observe the 1-second delay between the "Koin Modules Load" and the first "Koin Resolution" event in the Threads section.
Looking at the Screens section of the Timeline you can also observe that the 1-second delay in the initialization phase directly translated to a 1-second app startup delay before the first screen was loaded.
The detailed event sequence 👇 of the Timeline for this user session also shows the 1-second delay between the 'Koin Modules Load' and the first 'Koin Resolution' event. Immediately after the first Koin Resolution, we can observe the loading of the MainActivity.
This level of granularity allows you to focus your optimization efforts on the right area of the codebase, rather than hunting for performance problems throughout the entire startup sequence.
Based on the insights gained from the Kotzilla Platform, here are some key strategies you can employ to optimize your app's startup performance:
✅ Offload Heavy Tasks: Identify any resource-intensive operations that are being executed on the main thread during startup. Move these tasks to background threads to ensure the essential initialization steps can be completed without blocking the user interface.
✅ Implement Lazy Loading For non-essential features that aren't required for your app's initial launch, consider implementing lazy loading techniques. This allows you to defer the initialization of these components until they are actually needed, reducing the overall startup workload.
✅ Refactor Initialization Logic Closely examine the sequence of events during startup and look for opportunities to simplify and streamline your app's initialization logic. This may involve refactoring inefficient code, removing unnecessary steps, and generally optimizing the startup process.
The Kotzilla Platform's comprehensive performance monitoring and visualization capabilities allow you to go beyond surface-level metrics and diagnose the root cause of the startup time problems. This data-driven approach can enable teams to develop a targeted optimization strategy, ultimately improving the user experience by reducing the app's perceived launch time.
You can try the Kotzilla Platform for free. Tell us what you think.