Koin Dependency Injection (Android and KMP)

Pragmatic Kotlin DI. Koin vs Hilt: Koin runs in commonMain (Hilt doesn't) and verifies the graph via verify() instead of codegen; Hilt is Android-only with codegen + deep Jetpack integration (@HiltViewModel / hiltViewModel()). This reference covers the traps and boundaries, not the Classic DSL basics (single / factory / scoped / viewModel { } with get() resolution and runtime params, koinViewModel / koinInject, startKoin { androidLogger(); androidContext(this@MyApp); modules(...) }). Related: android-skills:kmp-ktor, android-skills:android-data-layer. Deps via koin-bom: koin-core, koin-android, koin-androidx-compose, koin-compose-viewmodel (KMP), koin-compose-viewmodel-navigation (Nav 3), koin-test, + optional koin-annotations / koin-ksp-compiler.

KSP Annotations — the generated-module accessor

@Module @ComponentScan discovers annotated classes and emits a module you pass to startKoin as UserModule().module — the generated .module extension on the annotated class is the part most often missed. Pick one style per module (don't mix Classic DSL + annotations inside a single module; switching between modules is fine).

@Single class UserRepositoryImpl(private val service: UserService) : UserRepository
@Factory class UserFormValidator
@KoinViewModel class UserDetailViewModel(
    @InjectedParam private val userId: String,
    private val repository: UserRepository,
) : ViewModel()
@Module @ComponentScan("com.example.feature.user") class UserModule
// startKoin { modules(UserModule().module) }