Clean Architecture patterns for Android and Kotlin Multiplatform projects — module structure, dependency rules, UseCases, Repositories, and data layer patterns. Use when structuring modules, layers, or data flow in an Android or KMP project.

Android Clean Architecture Clean Architecture patterns for Android and KMP projects. Covers module boundaries, dependency inversion, UseCase/Repository patterns, and data layer design with Room, SQLDelight, and Ktor. When to Activate Structuring Android or KMP project modules Implementing UseCases, Repositories, or DataSources Designing data flow between layers (domain, data, presentation) Setting up dependency injection with Koin or Hilt Working with Room, SQLDelight, or Ktor in a layered architecture Module Structure Recommended Layout Dependency Rules Critical : domain must NEVER depend on data , presentation , or any framework. It contains pure Kotlin only. Domain Layer UseCase Pattern Each UseCase represents one business operation. Use operator fun invoke for clean call sites: Domain Models Domain models are plain Kotlin data classes — no framework annotations: Repository Interfaces Defined in domain, implemented in data: Data Layer Repository Implementation Coordinates between local and remote data sources: Mapper Pattern Keep mappers as extension functions near the data models: Room Database (Android) SQLDelight (KMP) Ktor Network Client (KMP) Dependency Injection Koin (KMP friendly) Hilt (Android only) Error Handling Result/Try Pattern Use Result<T or a custom sealed type for error propagation: Convention Plugins (Gradle) For KMP projects, use convention plugins to reduce build file duplication: Apply in modules: Anti Patterns to Avoid Importing Android framework classes in domain — keep it pure Kotlin Exposing database entities or DTOs to the UI layer — always map to domain models Putting business logic in ViewModels — extract to UseCases Using GlobalScope or unstructured coroutines — use viewModelScope or structured concurrency Fat repository implementations — split into focused DataSources Circular module dependencies — if A depends on B, B must not depend on A References See skill: compose multiplatform patterns for UI patterns. See skill: kotlin coroutines flows for async patterns.

android-clean-architecture