Kmp

Mobile development is hard. Cross-platform mobile development is harder. Kotlin Multiplatform sits in the middle — shared business logic with native UI on each platform. The Gradle configuration alone can take hours. Can Claude handle it? This is the most technically challenging project in the entire series. KMP has expect/actual declarations, platform-specific dependency injection, multiplatform Gradle config, and two completely different UI frameworks (Jetpack Compose for Android, SwiftUI for iOS). ...

This is the hardest project in Part 2. Kotlin Multiplatform has a complex build system, platform-specific code patterns, and a Gradle configuration that can break in surprising ways. Can Claude handle it? I was skeptical going in. KMP projects have dozens of Gradle files, expect/actual declarations, and platform-specific dependencies that need to match exact versions. One wrong version number and nothing compiles. Total time: 4 hours 31 minutes. 6 prompts. Most of the time was fighting Gradle. ...

You have built a complete Ktor backend with authentication, database, WebSockets, Docker, and CI/CD. Now it is time to connect everything — a Kotlin backend and a Kotlin client sharing the same data models. In this final tutorial, you will create shared data models, build a Ktor Client that consumes your API, and see how a KMP mobile app connects to your backend. The Full-Stack Kotlin Vision Most full-stack projects look like this: ...

You have an existing Android app. It works. Users like it. Now the team wants an iOS version. Rewriting from scratch in Swift takes months. Kotlin Multiplatform lets you share the business logic and add iOS on top, without rewriting everything. In this final tutorial, we cover how to migrate an existing Android app to KMP. This is not a “rewrite from scratch” approach. It is a gradual migration — move one layer at a time, keep the Android app working at every step, and add iOS when the shared module is ready. ...

So far, our notes app runs on Android and iOS. The shared module handles business logic, networking, and database. The UI is platform-specific: Compose on Android, SwiftUI on iOS. But KMP can go further. With Compose Multiplatform, you can build desktop apps for Windows, macOS, and Linux. With Kotlin/Wasm, you can run Kotlin in the browser. In this tutorial, we explore both options — what they look like, how to configure them, and when they make sense. ...

Your notes app works on both Android and iOS. The data layer syncs, the UI layer has navigation and editing, and the shared ViewModel handles all business logic. Now it is time to publish. In this tutorial, you will learn how to build a release APK for Android, archive an IPA for iOS, set up GitHub Actions CI/CD, and prepare for the Play Store and App Store. What We Are Covering Android release build — signing, APK, AAB iOS release build — Xcode archive, IPA export GitHub Actions CI/CD — automated builds on every push Signing basics — keystores and provisioning profiles Store submission overview — Play Store and App Store requirements Android: Building a Release APK Debug vs Release So far, we have been building debug APKs with ./gradlew :composeApp:assembleDebug. Debug builds are not optimized and include debugging tools. For publishing, you need a release build. ...

In the previous tutorial, we built the shared data layer with Ktor, SQLDelight, and offline-first sync. The data layer works, but the UI is basic. You can only see a list of notes with a “+” button that creates placeholder notes. In this tutorial, we build a proper UI layer. You will add navigation between screens, a note editing screen with a color picker, pull-to-refresh sync, and loading and error states. All of this works on both Android (Compose) and iOS (SwiftUI). ...

In the previous tutorial, we set up the Notes app architecture with a local database and shared ViewModels. Everything works offline. But real apps need to sync with a server. In this tutorial, we build the shared data layer — adding a Ktor API client, Data Transfer Objects (DTOs), an offline-first sync pattern, and a database migration. All of this code lives in commonMain and runs on both Android and iOS. ...

Welcome to Part 4 of our KMP series — Build a Real App. In the next four tutorials, we build a complete cross-platform Notes app from scratch. This article covers the planning phase: architecture decisions, tech stack, project structure, and the initial setup that makes everything work on both Android and iOS. By the end of this tutorial, you will have a working project skeleton with shared business logic, a SQLDelight database, Koin dependency injection, and basic UI on both platforms. ...

Your app will crash. The network will fail. The server will return unexpected data. The database will be empty when it should not be. The question is not if errors happen — it is how you handle them. Good error handling makes the difference between an app that shows a helpful message and an app that shows a blank screen. In KMP, you need error handling that works on every platform. No Android-specific exceptions, no iOS-specific patterns. Shared error handling for shared code. ...