Android Startup Optimizer

Android Startup Performance Optimizer

Follow this structured workflow to diagnose, measure, and optimize Android application startup performance. Prioritize asynchronous lazy initialization and platform-native telemetry.

Android Vitals Thresholds

| Type | Target | Impact | |------|--------|--------| | Cold Start | `.

• Activity.onCreate(): Audit complex layout inflation, synchronous database/file access, heavy initial composition, or bitmap decoding on the main thread.

Implementation Patterns

// BAD: blocking Application.onCreate()
class MyApp : Application() {
    override fun onCreate() {
        super.onCreate()
        Firebase.initialize(this)
        MobileAds.initialize(this) // blocks main thread
        val config = File(filesDir, "config.json").readText() // disk I/O on main thread
    }
}

// GOOD: async + lazy application initialization
class MyApp : Application() {
    val container: AppContainer by lazy { AppContainerImpl(this) }
    private val applicationScope = CoroutineScope(SupervisorJob() + Dispatchers.Default)

    override fun onCreate() {
        super.onCreate()
        applicationScope.launch {
            Firebase.initialize(this@MyApp)
            MobileAds.initialize(this@MyApp)
        }
    }
}

// GOOD: Lazy Hilt injection in ViewModel
@HiltViewModel
class MainViewModel @Inject constructor(
    private val userRepository: UserRepository,           // eager — needed immediately
    private val analyticsTracker: Lazy, // lazy — deferred instantiation
) : ViewModel()

// GOOD: App Startup library initializer
class AdMobInitializer : Initializer {
    override fun create(context: Context) {
        Executors.newSingleThreadExecutor().execute { MobileAds.initialize(context) }
    }
    override fun dependencies() = emptyList>>()
}

Success Metrics

| Metric | Target | Tool | |--------|--------|------| | Cold Start p50 |

• Never recommend using lifecycleScope inside Application.onCreate(). You should recommend a custom CoroutineScope(SupervisorJob() + Dispatchers.Default) instead.
• For Android 15+, you must recommend the ApplicationStartInfo API for telemetry and the ProfilingManager API for system-triggered field traces.
• For Android 16+, you should recommend getStartComponent() on ApplicationStartInfo for component-specific optimizations.
• You must only wrap Hilt/Dagger dependencies in Lazy if they are not immediately needed.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: JosephSanjaya
• Source: JosephSanjaya/skills
• License: MIT

Install and usage instructions live in the source repository linked above.