For years, mobile developers have chased the holy grail: a single codebase for both Android and iOS that doesn't compromise on performance or user experience. Frameworks have come and gone, each with its own trade-offs. Now, in 2025, Kotlin Multiplatform (KMP) has emerged as a serious contender, not to replace native development, but to supercharge it.

But the question remains: is it just a cool experiment, or is it truly ready for the demands of a production application? The answer is a resounding yes, but it's not a silver bullet. This is an honest look at where KMP shines, where it stumbles, and whether it's right for your team.

The KMP Philosophy: Share Logic, Not UI

The most important thing to understand about KMP is what it is not. It is not a UI framework like React Native or Flutter. You do not write your UI once and run it everywhere. Instead, KMP focuses on sharing the non-UI parts of your app:

  • Business Logic: Validation, calculations, and state management.
  • Data Layer: Repositories, data sources, networking (Ktor), and database access (SQLDelight).
  • Data Models: Your plain data classes that represent the objects in your app.
  • ViewModels/Presenters: The architectural components that prepare data for the UI.

You still build your UI natively on each platform: Jetpack Compose for Android and SwiftUI for iOS. This "best of both worlds" approach means you get a truly native look, feel, and performance, while eliminating the massive problem of duplicating complex logic.

The Pros: Why Teams are Adopting KMP

Single Source of Truth

This is the biggest win. When your business logic for pricing, validation, or data syncing is in one shared module, you fix a bug once, and it's fixed everywhere. This drastically reduces inconsistencies between your Android and iOS apps.

Native Performance

Because the UI is 100% native, you don't pay the performance penalty associated with UI abstraction layers or bridges. Your app feels as fast and responsive as a traditionally built native app.

Gradual Adoption

You don't have to rewrite your entire app. You can start small by moving a single feature or data model into a shared KMP module. This makes it easy to try out KMP in an existing project without a massive upfront investment.

A Mature Core Ecosystem

The core technologies needed for a modern app are stable and production-ready:

  • Coroutines for asynchronous programming.
  • Ktor for networking.
  • Kotlinx.serialization for JSON parsing.
  • SQLDelight for type-safe local databases.
  • Koin/Kodein for dependency injection.

The Cons: An Honest Look at the Challenges

The Learning Curve

While your Android team will feel right at home with Kotlin, your iOS team will need to learn some Kotlin and get comfortable with the KMP project structure and build tools. This requires buy-in and training time.

The "Last Mile" Problem

Not every platform-specific API has a KMP equivalent out of the box. For things like Bluetooth, NFC, or specific OS-level integrations, you'll need to use Kotlin's expect/actual mechanism to write platform-specific implementations. This is powerful but adds complexity.

Example of `expect`/`actual` for a UUID 
// In your commonMain source set
expect fun randomUUID(): String

// In your androidMain source set
import java.util.UUID
actual fun randomUUID(): String = UUID.randomUUID().toString()

// In your iosMain source set
import platform.Foundation.NSUUID
actual fun randomUUID(): String = NSUUID().UUIDString()

Build and Tooling Complexity

A KMP project is inherently more complex than a standard Android project. You're dealing with multiple source sets (commonMain, androidMain, iosMain) and a Gradle setup that configures targets for the JVM, Android, and Native. While the tooling has improved immensely, it can still be a source of frustration.

The Verdict for 2025: KMP is absolutely production-ready. Companies like Netflix, Philips, and Square are using it to power major features in their apps. However, it's a strategic choice, not a default one.

KMP is a perfect fit if:

  • Your app has complex, critical business logic that must be consistent across platforms.
  • Your team is willing to invest in learning a new workflow.
  • You prioritize native UI performance above all else.

KMP might not be the right fit if:

  • Your app is very simple with minimal business logic.
  • Your primary goal is to build an app as quickly as possible with the smallest team, and you're willing to sacrifice some native feel (in which case Flutter might be a better choice).

Kotlin Multiplatform has matured from a promising idea into a powerful, pragmatic solution for modern mobile development. It offers a unique blend of code-sharing efficiency and native performance that is unmatched by other frameworks.