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Build Once, Run Anywhere: A Simple Weather App using Kotlin Multiplatform (KMM/KMP/CMP)

Simple Weather App using Kotlin Multiplatform (KMM/KMP)

⛆️ Build Once, Run Anywhere: A Simple Weather App using Kotlin Multiplatform (KMM/KMP/CMP)

🚀 In today’s cross-platform app development world, Kotlin Multiplatform (now popularly known as KMP or KMM) is a game-changer. It allows us to share business logic across Android and iOS without compromising the native feel and performance of the UI.

As a passionate mobile developer, I recently built a Simple Weather Application using KMP (Kotlin Multiplatform Project). This app is a real-world example of how you can target both Android and iOS platforms with a single codebase using:

  • 💻 Jetpack Compose for Android UI
  • 🍎 SwiftUI for iOS UI
  • ⚙️ Shared business logic in Kotlin
  • 🔗 GitHub Project Link

🌟 Why Kotlin Multiplatform (KMP)?

Unlike Flutter or React Native, KMP doesn't replace the native UI — instead, it empowers developers to write platform-specific UIs while keeping the core logic shared. This is a huge win for:

  • Code reuse (70–90%)
  • Native UX
  • Better app performance
  • Developer productivity

📱 Features of the Weather App

✅ Android (Jetpack Compose)

  • Clean, modern UI
  • Dark mode support
  • Animated backgrounds
  • Forecast list using LazyColumn

✅ iOS (SwiftUI)

  • Fully native SwiftUI layout
  • Adaptive UI for iPhone 16+
  • Seamless integration with shared logic from KMP

🌐 Shared Business Logic (KMM)

  • Uses Kotlin Flow for reactive data streams
  • Weather data from Open-Meteo API
  • Caching with SQLDelight
  • Dependency Injection with Koin

📦 Libraries & Tools Used

Purpose Library / Tool
UI - AndroidJetpack Compose
UI - iOSSwiftUI
NetworkingKtor
Dependency InjectionKoin
SerializationKotlinx.serialization
Local StorageSQLDelight
ViewModelKotlin Coroutines + StateFlow
NavigationCompose Navigation + SwiftUI NavigationStack

👨‍💻 Learning Resource for Developers

You can clone this project from GitHub and learn how to:

  • Structure a shared KMM project
  • Use Compose + SwiftUI together
  • Implement clean architecture with shared state
  • Handle weather APIs with caching and reactivity

🔗 GitHub Repository

🔥 Why This Matters in 2025

With Apple’s new Glass UI and spatial computing (visionOS), native-first solutions like KMP/CMP will become even more crucial. Your project remains future-proof by respecting platform guidelines and maximizing performance.

🏁 Final Thoughts

This project is perfect for:

  • Learners exploring KMP/KMM
  • Developers building cross-platform POCs
  • Startups looking for shared logic without UI compromise

Feel free to ⭐️ star the repo and share feedback!

📣 Trending Hashtags

#KMM #KMP #CMP #KotlinMultiplatform #ComposeMultiplatform #JetpackCompose #SwiftUI #AndroidDevelopment #iOSDevelopment #CrossPlatform #OpenSource #WeatherApp #Kotlin #Ktor #Koin #SQLDelight #KotlinConf2025

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