Kotlin Multiplatform Development: A Comprehensive Guide

In this Kotlin Multiplatform Development Comprehensive Guide, we will explore everything you need to know about Kotlin Multiplatform Development, from its core concepts and features to its advantages, challenges, and real-world applications. 

Whether you’re a seasoned developer or a business, this comprehensive resource will provide valuable insights to help you make the most of Kotlin Multiplatform in your projects.

Overview of Kotlin and Kotlin Multiplatform Development

Before diving into the Kotlin multiplatform development comprehensive guide, let’s get an overview of what Kotlin app development is and how it relates to KMP. 

Kotlin, a programming language designed by JetBrains, has gained widespread popularity for its concise syntax, seamless interoperability with Java, and first-class support for Android development. 

Comprehensive Guide: Kotlin vs Java ➜

Building on the success of Kotlin, Kotlin Multiplatform Development enables developers to share common business logic and other non-UI code between multiple platforms, reducing redundancy and improving productivity.

Unlike traditional cross-platform solutions that aim to unify the entire development process, Kotlin Multiplatform Development takes a unique, modular approach. It allows developers to write platform-agnostic code while preserving the ability to integrate deeply with native APIs. 

This balance of shared and platform-specific code is a game-changer for businesses and developers aiming to optimize time, cost, and resource efficiency without compromising performance or user experience.

Understanding Kotlin Multiplatform Development

In this section, we’ll delve into the fundamentals of Kotlin Multiplatform Development. We’ll cover what it is, how it works, and when it’s the right choice for your project.

What is Kotlin Multiplatform Development?

Kotlin Multiplatform (KMP) Development leverages a powerful technology that lets you create apps for multiple platforms, including iOS, Android, macOS, Windows, Linux, and more. It allows you to write and share code efficiently across these platforms, while still achieving the speed and performance of native apps.

Build Your Kotlin Multiplatform App Now ➜

How Kotlin Multiplatform Development Works

At its core, Kotlin Multiplatform (KMP) Development allows the sharing of common code, such as data models, network requests, and business logic, across platforms. 

This shared code is written in Kotlin and compiled into platform-specific binaries, ensuring optimal performance and compatibility. 

The platform-specific code—such as user interface components—can still be written in native languages like Swift for iOS or Java for Android, providing full access to native APIs.

How KMP Development Differs from Traditional Cross-Platform Development

Unlike frameworks like Flutter or React Native, which emphasize a single codebase for the entire application (including the UI), Kotlin Multiplatform emphasizes modularity. 

Kotlin Multiplatform Development allows developers to decide which parts of the application should be shared and which should remain platform-specific. This gives developers greater control over the development process and enables them to maintain the performance and look-and-feel of native applications.

Use Cases for Kotlin Multiplatform Development

Popular use cases of Kotlin Multiplatform (KMP) Development include: 

1. Share Logic While Keeping the UI Native
   KMP enables developers to build apps with shared business logic while maintaining platform-specific UIs. For example, you can create a mobile app in Android Studio that works seamlessly on both Android and iOS.
2. Share Both Logic and UI
   With tools like Compose Multiplatform, KMP allows sharing both logic and UI across platforms. Developers can build applications with a unified codebase for Android, iOS, and desktop environments.
3. Share Specific Logic Layers
   KMP is ideal for sharing specific application layers, such as the data access layer, between platforms. This approach allows developers to use shared code for backend or network logic across Android and iOS.
4. Expand Existing Applications to Multiple Platforms
   KMP enables existing Android apps to become multiplatform by introducing shared logic for iOS compatibility, allowing developers to target a wider audience with minimal code duplication.

Kotlin Multiplatform Development empowers developers to optimize their workflows by eliminating duplication while retaining the benefits of native development. This makes it an ideal solution for businesses aiming to deliver consistent, high-quality experiences across platforms.

Related Articles:

• Kotlin Android App Development: The Complete Guide for Modern Android Apps
• Kotlin Game Development: A Complete Guide

Key Features of Kotlin Multiplatform Development

Kotlin Multiplatform (KMP) stands out from other cross-platform frameworks due to its unique features that prioritize flexibility, efficiency, and seamless integration with native platforms. 

Here are 10 key features that make KMP Development a preferred choice for modern cross-platform development:

1. Source Sets for Shared and Platform-Specific Code
2. Multiplatform Targets (JVM, Native, JavaScript, WebAssembly)
3. Gradle Multiplatform Plugin
4. Kotlin/Native for iOS, macOS, and other non-JVM targets
5. Expect/Actual Mechanism
6. Compose Multiplatform for Shared UI
7. Interoperability with Platform Languages (E.g. Java/Swift)
8. Platform-specific Debugging and Testing Support
9. Built-In Concurrency Support Using Coroutines
10. Support for Dependency Injection

Kotlin Multiplatform’s combination of shared logic, native performance, and flexible customization makes it a compelling choice for teams looking to streamline their development process while delivering high-quality applications across platforms.

Advantages of Kotlin Multiplatform Development

Kotlin Multiplatform (KMP) offers a wealth of benefits for developers and businesses alike, making it a powerful tool for cross-platform application development. 

Below are 10 key advantages that highlight why Kotlin Multiplatform is gaining traction:

1. Kotlin Multiplatform Avoids Code Duplication
2. Kotlin Multiplatform Supports UI Code Sharing
3. Kotlin Multiplatform Supports Gradual Code Sharing
4. Kotlin Multiplatform is Trusted by Global Companies
5. Kotlin Multiplatform is Backed by a Large Community
6. Kotlin Multiplatform Provides Powerful Tooling Support
7. Kotlin Multiplatform Works for Existing and New Projects
8. Kotlin Multiplatform Allows Simplified Code-Sharing Mechanisms
9. Kotlin Multiplatform Enables Flexible Cross-platform Development
10. Kotlin Multiplatform Supports Multiple Platforms (Android, iOS, web, desktop, etc.)

Kotlin Multiplatform (KMP) is not just a tool—it’s a strategic asset for businesses aiming to streamline their development processes and deliver consistent, high-quality applications. By leveraging the advantages of KMP, teams can achieve a harmonious balance between shared logic and native customization.

Read More: Benefits of Kotlin for App Development ➜

Challenges in Kotlin Multiplatform Development

While Kotlin Multiplatform (KMP) offers numerous advantages, it is not without its challenges. Understanding these potential hurdles can help teams make informed decisions and implement strategies to mitigate them effectively.

Below are 9 challenges of Kotlin Multiplatform Development:

1. Lack of Tooling Maturity
2. Limited Ecosystem Compared to Flutter or React Native
3. Learning Curve for Developers Unfamiliar with Kotlin
4. Platform-Specific Code Challenges
5. Performance Trade-offs in Some Cases
6. Debugging Complexity Across Multiple Platforms
7. Limited Use Cases for Some Applications
8. Complex Dependency Management
9. Limited API and Library Compatibility

How to Address These Challenges

Despite these limitations, Kotlin Multiplatform is a powerful framework with significant potential. By staying updated with the latest KMP releases, leveraging community support, and following best practices, developers can overcome these challenges and maximize the benefits of Kotlin Multiplatform.

Kotlin Multiplatform Development Step by Step Guide

Starting your Kotlin Multiplatform (KMP) Development journey requires a clear understanding of its setup, tools, and structure. Follow these steps to get started with Kotlin Multiplatform development.

1. Prerequisites

Before diving into KMP Development, ensure you have the following:

• A basic understanding of the Kotlin programming language.
• Development tools installed: IntelliJ IDEA (Community or Ultimate Edition) or Android Studio.
• Knowledge of native development for Android (Kotlin/Java) and iOS (Swift/Objective-C) is helpful but not mandatory.

2. Setting Up Your Development Environment

To set up your Kotlin Multiplatform Development Environment:

• Install IntelliJ IDEA or Android Studio: Both IDEs are optimized for Kotlin development and come with the necessary Gradle plugins for KMP.
• Add the Kotlin Multiplatform Plugin: Ensure your project is set up with the kotlin multiplatform plugin for Android Studio to enable multiplatform development.
• Launch Xcode at least once and accept the terms of use (to build iOS apps).

3. Creating a Kotlin Multiplatform Project

Use the Kotlin Multiplatform Wizard to create a new Kotlin Multiplatform project:

1. In “New Project” add your desired “Project Name” and “Project ID”
2. Choose the platforms you want to target (e.g., Android, iOS, Desktop, Web, or Server).
3. Click the Download button and unpack the archived file.

4. Understanding the Project Structure

A typical Kotlin Multiplatform project includes three modules:

• Shared Module: Contains common code for business logic, networking, and data models. E.g. androidMain, commonMain, and iosMain.
• Platform-Specific Modules: Includes code unique to each platform (e.g., for Android it’s composeApp and for iOS its iosApp).
• Expect/Actual Declarations: Use expect in shared code to define platform-specific functionality and implement it using actual in platform-specific modules.

5. Writing Shared Code

Write the shared code first using Kotlin in the shared module. You can:

• Implement common tasks such as API requests, data serialization, and utility functions.
• Leverage Kotlin libraries like kotlinx.serialization for serialization and kotlinx.coroutines for asynchronous programming.

6. Adding Platform-Specific Code

Next up, add platform specific code to give your applications a native feel:

• For Android, use Kotlin or Java to implement platform-specific features.
• For iOS, use Swift or Objective-C.
• Bridge shared and platform-specific code using expect/actual declarations or dependency injection.

7. Testing and Debugging

Finally, ensure you properly test and debug your Kotlin Multiplatform (KMP) application. Some common tests include:

• Unit Testing: Write unit tests for shared code using the Kotlin Test framework.
• Platform-Specific Testing: Test native modules using their respective tools (e.g., Xcode for iOS and Android Studio for Android).
• Debug shared and platform-specific code using the debugging tools provided by your IDE.

Test Your Kotlin Multiplatform App ➜

8. Building and Running Your Application

You can now build and run your KMP application.

• Use Gradle tasks to build and package your application for each platform.
• For Android, run the app through Android Studio.
• For iOS, integrate the shared code with Xcode and run the app on a simulator or device.

9. Expanding Your Project

This short guide was a starting point for KMP development. You can:

• Gradually add more shared functionality as your familiarity with Kotlin Multiplatform grows.
• Explore Kotlin Multiplatform libraries to extend your project’s capabilities.

Getting started with Kotlin Multiplatform may require some initial setup and learning, but the long-term benefits of shared logic, efficiency, and flexibility make it a worthwhile investment for modern cross-platform development.

Best Practices for Kotlin Multiplatform Development

Adopting Kotlin Multiplatform (KMP) successfully requires not only understanding its features but also following best practices to maximize productivity, maintainability, and performance. 

Here are some key practices to keep in mind for Kotlin Multiplatform Development:

1. Start Small and Make Incremental Adjustments
2. Prioritize Business Logic for Sharing
3. Leverage Expect/Actual Mechanism Effectively
4. Optimize Build Configuration With Gradle
5. Use Multiplatform Libraries Like Ktor, kotlinx.serialization, and kotlinx.coroutines
6. Write Platform-Agnostic Shared Code
7. Conduct Thorough Testing
8. Use Dependency Injection (DI)
9. Maintain Clear Documentation
10. Plan for Scalability
11. Monitor Performance of Your KMP application
12. Stay Updated with Kotlin Ecosystem

By adopting these best practices, you can ensure a smoother development experience and maximize the benefits of Kotlin Multiplatform. These guidelines will help you build robust, maintainable, and high-performing applications that delight users across platforms.

Real-World Use Cases of Kotlin Multiplatform Development

Kotlin Multiplatform (KMP) Development is increasingly being adopted by companies and developers to solve a variety of cross-platform challenges. The flexibility of KMP allows it to be used in a wide range of scenarios, from small applications to large-scale enterprise solutions. 

Here are some notable real-world use cases that demonstrate the power and potential of Kotlin Multiplatform:

1. McDonald’s – Uses KMP for their Global Mobile App
2. Phillips – Uses KMP for their HealthSuite Digital Platform mobile SDK
3. Netflix – Built their experience management tool, Hendrix Multiplatform SDK using KMP
4. Forbes – Uses KMP to share 80% of logic across iOS and Android

Kotlin Multiplatform is already making an impact across various industries by simplifying cross-platform development, reducing redundancies, and enhancing consistency. Whether it’s building mobile apps, libraries, IoT systems, or even full-stack solutions, KMP is proving to be a flexible and scalable solution for modern development needs.

Kotlin Multiplatform Development vs. Other Cross-Platform Solutions

In this section, we’ll compare Kotlin Multiplatform Development with some of the leading cross-platform development tools like Flutter, React Native, and Xamarin.

When choosing a cross-platform solution for mobile and other multi-platform development, it’s important to compare Kotlin Multiplatform (KMP) with other popular frameworks. Each solution comes with its own set of strengths and weaknesses. 

Kotlin Multiplatform Development vs. Flutter Development

Flutter is a popular UI-centric cross-platform framework developed by Google, primarily for mobile and web apps. Unlike Kotlin Multiplatform, which allows developers to share business logic and core features, Flutter shares the entire codebase for both UI and business logic across platforms.

If your project requires deep integration with native UIs and you need more control over platform-specific features, Kotlin Multiplatform is a great choice. Flutter, on the other hand, is ideal for projects that need a consistent UI across platforms with a single codebase.

Kotlin Multiplatform Development vs. React Native Development

React Native is another popular cross-platform framework that uses JavaScript (or TypeScript) to build mobile applications. It allows developers to write shared business logic and UI components that work across Android and iOS.

React Native is best for projects where quick development and reusable UI components are the priority. Kotlin Multiplatform, however, is a better choice when you need fine-grained control over native UI and platform-specific logic while sharing only the business logic between platforms.

Kotlin Multiplatform Development vs. Xamarin Development

Xamarin is a cross-platform framework developed by Microsoft that allows developers to write C# code that runs on Android, iOS, and even Windows applications. It offers a unified platform for building cross-platform applications using .NET libraries.

Xamarin is a great choice for teams already working within the .NET ecosystem and those who prefer using C#. Kotlin Multiplatform offers more flexibility for teams looking for a lighter framework that emphasizes shared logic without forcing a complete rewrite of the user interface.

Which Framework is Right for You?

• If you’re focused on sharing business logic while maintaining native UIs and optimal performance, Kotlin Multiplatform is an excellent choice.
• For a unified solution that handles both UI and logic with a single codebase, Flutter is ideal.
• If your team is experienced with JavaScript and needs to leverage native components, React Native may be the way to go.
• If your organization is invested in the Microsoft ecosystem and prefers C#, Xamarin could be the best fit.

Each framework has its strengths, so the best solution depends on your project’s specific requirements, the team’s skillset, and the platform targets you aim to support.

The Future of Kotlin Multiplatform Development

Kotlin Multiplatform (KMP) has quickly gained momentum in the developer community and is expected to play a significant role in the future of cross-platform development. 

As more developers and companies recognize the benefits of sharing business logic and core functionality across platforms, KMP is poised to grow and evolve. In May 2024, during Google I/O, Google officially announced their official support for Kotlin Multiplatform (KMP) to share business logic across Mobile, Web, Server, and Desktop.

Expected Improvements in the Future for Kotlin Multiplatform Development:

1. Increased Platform Support to WebAssembly, Embedded Systems, and IoT
2. Improved Tooling and IDE Support for Better KMP Development
3. Expanding Library Ecosystem and Third-Party Integrations
4. Kotlin Multiplatform Mobile (KMM) Advancements for iOS
5. Greater Adoption in the Industry

The future of Kotlin Multiplatform looks incredibly promising. With continuous improvements to tooling, expanded platform support, and a growing library ecosystem, KMP is set to become a leading solution for cross-platform development. 

As more companies and developers embrace its flexibility, we can expect Kotlin Multiplatform to revolutionize how mobile, desktop, and web applications are developed—offering a unified approach without compromising on performance or native experience.

Conclusion

Kotlin Multiplatform (KMP) is emerging as a game-changing solution for cross-platform development, offering a unique combination of shared logic and platform-specific customization. By enabling developers to write once and deploy across multiple platforms, Kotlin Multiplatform significantly reduces redundancy and development costs, all while ensuring native performance and UI experiences on each platform.

In this guide, we’ve explored the key aspects of Kotlin Multiplatform, including its advantages, challenges, real-world use cases, and how it stacks up against other cross-platform solutions like Flutter, React Native, and Xamarin. From its impressive support for Android, iOS, web, and desktop to its growing ecosystem and community, KMP is quickly becoming a powerful tool for developers seeking efficient, maintainable, and scalable cross-platform solutions.

As Kotlin Multiplatform continues to mature, we can expect further innovations in platform support, tooling, and community contributions. The increasing demand for seamless multi-platform development will only fuel its growth, making KMP a valuable framework for mobile developers, backend engineers, and even teams working on IoT or embedded systems.

For businesses and developers who prioritize performance, flexibility, and sharing core business logic without sacrificing native experiences, Kotlin Multiplatform is definitely a framework to watch. Whether you’re building a mobile app, a backend system, or a cross-platform library, KMP provides the tools and scalability to meet the needs of modern development.

FAQs on Kotlin Multiplatform Development

We conclude our comprehensive guide on Kotlin Multiplatform development with some frequently asked questions (FAQs). If you are considering implementing KMP in your next project, rest assured that the framework offers a robust solution for building modern, efficient, and scalable applications across platforms. 

What is Kotlin Multiplatform Development?

Kotlin Multiplatform is a versatile technology that enables developers to build applications for multiple platforms while reusing significant portions of the codebase. This approach preserves the advantages of native programming and supports platforms like iOS, Android, macOS, Windows, Linux, and more.

Is KMP better than Flutter?

The choice between Kotlin Multiplatform and Flutter depends on your specific project requirements. Flutter may be better suited for teams focusing on rapid development or MVPs, especially if they are comfortable adopting Dart. On the other hand, Kotlin Multiplatform is ideal for projects prioritizing native performance and flexibility.

How is Kotlin Multiplatform different from Kotlin/Native?

Kotlin Multiplatform enables code sharing across platforms, while Kotlin/Native specifically targets compiling Kotlin into native binaries via LLVM. Kotlin/Native supports platforms like Windows, Linux, macOS, iOS, and WebAssembly. In contrast, Kotlin Multiplatform encompasses all targets, including JVM and JavaScript, beyond just native binaries.

Is Kotlin good for cross-platform?

Absolutely! Kotlin is an excellent choice for cross-platform as well as single-platform development. It opens up opportunities across mobile, backend, desktop, and multiplatform development with its clean syntax and robust features.

Does Netflix use Kotlin Multiplatform?

Yes, Netflix leverages Kotlin Multiplatform to improve product reliability and accelerate delivery. Kotlin’s safety and concise syntax allow Netflix to streamline their app’s development and optimize its codebase.

Is Kotlin Multiplatform worth learning?

Yes! Kotlin Multiplatform is highly beneficial for developers. It simplifies cross-platform development by reducing redundant code while preserving native programming advantages, making it a valuable skill for modern developers.

Can I use Java in Kotlin Multiplatform?

Yes, Java can be used in Kotlin Multiplatform projects, though it’s generally recommended only when necessary. In JVM modules, you can incorporate Java libraries or even write Java code to complement Kotlin sources.

Is Kotlin Multiplatform free?

Yes, Kotlin Multiplatform is open-source and freely available. Developers can use IntelliJ IDEA’s free Community Edition to start building KMP projects by installing the Kotlin Multiplatform Wizard plugin.

Are Kotlin and Kotlin Multiplatform the same?

No. Kotlin is a programming language, while Kotlin Multiplatform is a framework for sharing Kotlin code across multiple platforms, enabling efficient cross-platform development.

What is the main function of Kotlin Multiplatform?

Kotlin Multiplatform is designed to simplify cross-platform development by enabling the sharing of business logic between platforms like Android and iOS. This reduces development time while maintaining native performance and flexibility.

What is the difference between Kotlin Multiplatform vs Compose Multiplatform?

Kotlin Multiplatform focuses on sharing business logic across various platforms, while Compose Multiplatform expands this functionality to UI code. Compose Multiplatform adopts the declarative UI patterns of Jetpack Compose, enabling shared UI development across platforms.

Who developed Kotlin Multiplatform?

JetBrains developed Kotlin Multiplatform using the Kotlin programming language. It supports stable, production-ready mobile platforms and continues to evolve to meet cross-platform development needs.

Can Kotlin Multiplatform replace native app development?

No, Kotlin Multiplatform is not designed to replace native app development but to complement it. While it allows sharing business logic across platforms, the UI and platform-specific features are still implemented natively, ensuring native performance and experience. It’s an excellent choice for projects that need to balance code sharing with maintaining native app quality.

What platforms are supported by Kotlin Multiplatform?

Kotlin Multiplatform supports a wide range of platforms, including Android, iOS, web, desktop, server-side environments, and more.

How does Kotlin Multiplatform ensure code sharing?

Kotlin Multiplatform uses source sets, which are collections of source files with specific dependencies, compiler options, and targets. These source sets are the primary mechanism for sharing code across multiple platforms in KMP projects.

Is Kotlin Multiplatform suitable for small-scale projects?

Yes, Kotlin Multiplatform is ideal for projects of all sizes. Its flexibility and efficiency make it valuable for small-scale projects while remaining robust enough to handle complex, large-scale applications.

What are the tools needed to start with KMP?

To start with Kotlin Multiplatform (KMP), you’ll need the following tools:

1. IntelliJ IDEA or Android Studio (with Kotlin plugin).
2. Kotlin Multiplatform Wizard plugin for project setup.
3. Gradle for dependency management and build automation.
4. Optional: Xcode for iOS development.

These tools provide the necessary environment for developing and managing KMP projects efficiently.

What are Kotlin Multiplatform targets, and how do they work?

Targets represent the platforms to which Kotlin compiles shared code. Examples include the JVM, JavaScript, Android, iOS, and Linux. Each target acts as a specific compilation destination for the common and platform-specific code in a KMP project.

Does Kotlin Multiplatform support iOS and Android equally?

Kotlin Multiplatform supports both iOS and Android, though Android integration is more seamless because Kotlin is natively compatible with the JVM. iOS support is strong but requires additional setup for native tooling and frameworks.

How secure is Kotlin Multiplatform for production applications?

Kotlin Multiplatform is secure for production, as it uses Kotlin’s type safety and robust error handling. Its security also depends on the implementation of best practices and secure coding standards.

What are the debugging tools available for KMP?

Debugging tools for KMP include IntelliJ IDEA, Android Studio, and platform-specific debuggers like Xcode for iOS. These tools provide robust support for debugging shared and platform-specific code.

What are the licensing and cost implications of using Kotlin Multiplatform?

Kotlin Multiplatform is open-source and free to use. IntelliJ IDEA offers a free Community Edition with KMP support, making it cost-effective for developers and organizations.

What is the future of Kotlin Multiplatform?

The future of Kotlin Multiplatform is promising, with growing community adoption, expanded platform support (e.g., WebAssembly), and improvements in tooling, libraries, and performance for efficient cross-platform development.

This page was last edited on 23 December 2024, at 2:36 pm