Kotlin Multiplatforms

The last few decades were completely for the evolution of technology in various fields, 90s mobile phones were considered a luxury, but now they have turned to our basic need because as the evolution of technology. Today we have multi-platforms such as Android, iOS, web, etc. Enter Kotlin Multiplatform (KMP), a revolutionary approach designed to simplify cross-platform development by enabling code sharing across Android, iOS, desktop, and even web platforms. This article explores what Kotlin Multiplatform is, why it’s worth considering, its key benefits, and what it looks like from the perspective of an Android developer.

What is Kotlin Multiplatform?

Kotlin Multiplatform is a feature of the Kotlin programming language developed by JetBrains. It allows developers to write code once and share it across multiple platforms while retaining the ability to write platform-specific code where needed. Unlike other cross-platform frameworks like Flutter or React Native, KMP doesn’t aim to replace native development; instead, it facilitates code sharing for parts of an application, such as business logic, data handling, and domain-specific functionality.

Kotlin Multiplatform comprises three main components:

1. Common Code: Shared code written in Kotlin, which is platform-agnostic.
2. Platform-Specific Code: Extensions or implementations specific to Android, iOS, or other platforms.
3. Kotlin/Native, Kotlin/JS, and JVM Targets: Tools enabling Kotlin to compile to native binaries, JavaScript, or the JVM.

This modular approach allows developers to reuse as much code as possible while tailoring the app’s behavior to individual platforms.

Why Should We Use Kotlin Multiplatform?

The rise of Kotlin Multiplatform comes from the need to address inefficiencies in multi-platform development. Developers often spend considerable time duplicating and maintaining the same functionality across separate codebases for Android, iOS, and other platforms. Kotlin Multiplatform solves this by enabling the following:

1. Code Reusability

Core logic, such as network requests, data serialization, or business rules, can be written once in Kotlin and shared across platforms. This reduces redundancy and improves productivity.

2. Platform-Specific Flexibility

KMP doesn’t enforce a “write once, run anywhere” philosophy. It allows platform-specific customization when necessary. For instance, you can write custom UI code for Android in Jetpack Compose and for iOS using SwiftUI.

3. Ecosystem Integration

As a Kotlin feature, KMP seamlessly integrates into existing Kotlin-based projects. For Android developers, using KMP feels like an extension of their current development flow rather than adopting an entirely new framework.

4. Modern Tooling

JetBrains provides excellent tools for KMP development through IntelliJ IDEA and Android Studio, making it easier to debug, test, and deploy shared and platform-specific code.

Benefits of Kotlin Multiplatform

Kotlin Multiplatform brings a host of advantages to cross-platform development. Here are some of the most notable:

1. Reduced Development Costs

Sharing code between platforms reduces the time and cost of development. Instead of maintaining multiple codebases, teams can focus on a single shared codebase for core logic while writing platform-specific code only when needed.

2. Improved Code Quality

By centralizing the business logic, KMP minimizes the risk of inconsistencies and discrepancies between platforms. Any bug fixes or updates in the shared codebase are automatically reflected across all platforms.

3. Developer Productivity

Developers can focus on writing better code instead of duplicating it. This leads to faster iteration cycles and streamlined workflows, especially in Agile teams.

4. Performance

KMP doesn’t compromise performance. The shared code is compiled into native binaries or JVM bytecode, ensuring that the app runs efficiently on each platform.

5. Interoperability with Native Code

Kotlin Multiplatform is designed to interoperate with platform-native languages like Swift for iOS and Java/Kotlin for Android. This makes it easier to integrate with existing native codebases or use native libraries.

Kotlin Multiplatform for an Android Developer

For an Android developer, Kotlin Multiplatform feels like a natural extension of the Kotlin language. Here’s what the development process looks like:

1. Setting Up a Kotlin Multiplatform Project

Kotlin Multiplatform projects use Gradle as the build system. A typical project has the following structure:

- shared/
  - src/
    - commonMain/ (Shared code for all platforms)
    - androidMain/ (Android-specific code)
    - iosMain/ (iOS-specific code)
- androidApp/ (Android application code)
- iosApp/ (iOS application code)

The commonMain directory contains the shared code, such as data models, API clients, or business logic, while androidMain and iosMain include platform-specific implementations.

2. Using Shared Code in Android

As an Android developer, you’ll consume the shared Kotlin code as you would any other Kotlin library. For example, if the shared module provides a repository for fetching data, you can directly call its methods in your Android code.

3. Integration with Android Studio

Since Android Studio is based on IntelliJ IDEA, it supports Kotlin Multiplatform out of the box. You can debug, test, and build your Android application alongside the shared code seamlessly.

4. Testing Shared Code

Kotlin Multiplatform supports writing tests in the shared module. This means you can test your business logic once and ensure it works across platforms, saving significant time.

Use Cases for Kotlin Multiplatform

1. Cross-Platform Mobile Applications

Building apps for Android and iOS is the most common use case for Kotlin Multiplatform. It allows teams to share core logic while maintaining platform-specific UI experiences.

2. Shared Libraries

KMP is ideal for creating libraries that can be used across different platforms, such as analytics modules, authentication libraries, or reusable UI components.

3. Enterprise Applications

Organizations often have internal tools that need to run on multiple platforms. Kotlin Multiplatform can streamline the development of such tools.

Challenges and Limitations

While Kotlin Multiplatform is promising, it’s important to consider its challenges:

1. Learning Curve: For teams unfamiliar with Kotlin or multi-platform development, the initial setup and architecture design can be daunting.
2. Limited Third-Party Libraries: Not all libraries support KMP, which may require developers to write platform-specific code or use alternatives.
3. Ecosystem Maturity: Although growing rapidly, Kotlin Multiplatform is still evolving, and some features may lack the polish of more mature frameworks.

Conclusion

Kotlin Multiplatform is a game-changer for cross-platform development. By enabling code sharing while retaining platform-specific flexibility, it strikes a perfect balance between efficiency and customization. For Android developers, KMP is an extension of the familiar Kotlin ecosystem, making it easier to adopt without reinventing the wheel.

While there are challenges, the benefits of reduced development costs, improved code quality, and increased productivity make Kotlin Multiplatform a compelling choice for modern app development. As the ecosystem continues to grow, KMP is poised to become a standard approach for building robust, scalable, and maintainable multi-platform applications.

If you’re an Android developer looking to expand your skill set or streamline your cross-platform projects, Kotlin Multiplatform is well worth exploring.