Why Koin Is More Suitable Than Hilt for Dependency Injection in Modern Android Development

In modern software development, Dependency Injection (DI) is a widely used design pattern that decouples code, improves modularity, and enhances testability. Android developers commonly choose between Hilt and Koin as DI frameworks.

What is Dependency Injection?

DI moves the responsibility of providing an object's dependencies from the object itself to an external container, offering benefits such as code decoupling, easier testing with mocks, and simplified maintenance.

class UserRepository {
    fun getUser(): String = "User Data"
}

class UserService {
    private val userRepository = UserRepository()
    fun getUserInfo(): String {
        return userRepository.getUser()
    }
}

Without DI, UserService is tightly coupled to UserRepository . Using DI, the same functionality can be expressed with interfaces and constructor injection:

interface UserRepository {
    fun getUser(): String
}

class UserRepositoryImpl : UserRepository {
    override fun getUser(): String = "User Data"
}

class UserService(private val userRepository: UserRepository) {
    fun getUserInfo(): String = userRepository.getUser()
}

Inversion of Control (IoC)

IoC is a broader principle where the control of object creation and lifecycle is handed over to a framework or container. DI is a concrete implementation of IoC.

Why Use DI in ViewModel?

Without a DI framework, passing parameters to a ViewModel requires a custom ViewModelProvider.Factory , which adds boilerplate and complexity, especially when multiple parameters or different repository implementations are needed.

class UserViewModel(private var id: String?) : ViewModel()

class UseViewModelFactory(private val id: String?) : ViewModelProvider.Factory {
    override fun
create(modelClass: Class
): T {
        if (modelClass.isAssignableFrom(UserViewModel::class.java)) {
            return UserViewModel(id) as T
        }
        throw IllegalArgumentException("Unknown ViewModel class")
    }
}

With Koin, the same can be achieved with a concise DSL:

val userModule = module {
    viewModel { (id: String) -> UserViewModel(id) }
}

Initialization in Application.onCreate :

override fun onCreate() {
    super.onCreate()
    startKoin {
        androidLogger()
        androidContext(this@MyApplication)
        modules(userModule)
    }
}

And usage in a composable:

@Composable
fun UserScreen(id: String?, viewModel: UserViewModel = koinViewModel { parametersOf(id) }) {
    // UI content
}

Multi‑module Communication

Koin also supports service interfaces across modules. Define an interface in a base module:

interface IUserService {
    fun getUserInfo(): Flow
}

Implement it in a feature module and register with Koin:

class IUserServiceImpl : IUserService {
    override fun getUserInfo(): Flow
= TODO()
}

val userModule = module {
    single
{ IUserServiceImpl() }
}

Inject the service where needed:

private val userService: IUserService? by injectOrNull(IUserService::class.java)
userService?.getUserInfo()?.collect { /* ... */ }

Why Choose Koin?

Simple and developer‑friendly: Clean DSL, no compile‑time overhead, minimal setup.

Lightweight: Suitable for both small and large projects.

Runtime safety checks: Validates dependency graphs; an IDE plugin is forthcoming.

Kotlin Multiplatform support: Same DI code can run on Android, iOS, desktop, and web.

Excellent Jetpack Compose integration: Directly inject ViewModels with koinViewModel .

Comparison with Hilt

No annotation processor: Hilt requires hilt-compiler , increasing build time; Koin uses pure Kotlin DSL.

Lower learning curve: Hilt needs many annotations ( @HiltViewModel , @Inject , @Module , @AndroidEntryPoint ), whereas Koin configuration is straightforward.

Performance: Benchmarks show comparable runtime performance.

IDE navigation: Hilt provides navigation icons; Koin’s plugin is in development.

Cross‑platform capability: Hilt is tied to Android/Dagger, while Koin works across Kotlin Multiplatform.

Official support: Hilt is part of Android Jetpack; Koin is backed by the Kotzilla team and the Kotlin Foundation.

Conclusion

Koin’s simplicity, lack of compile‑time code generation, lightweight nature, and multiplatform support make it a compelling choice for new Android projects and for gradually migrating existing projects away from Hilt.