Now when you rebuild the iOS app, you might not notice anything immediately, but you can remove the Platform_iosKt prefix and let the platform() function act as a global function. Explore how to set up and build your first Android and iOS application with Kotlin & Compose Multiplatform. We should leverage the internal modifier to ensure that functions, properties, classes, objects, and interfaces are only visible within the same module. In some cases, we may need to use the public modifier to make elements accessible to other Kotlin modules, but iOS doesn’t necessarily need access to them. To exclude these from the iOS compilation, we can use the @HiddenFromObjC annotation which prevents a function or property from being exported. That’s why expected and actual declarations should be defined in the same package – they are merged into one declaration in the resulting platform code.

Step 1: Create a New Project

As of 2024, JavaScript, HTML, Python, SQL, and TypeScript were the most widely used languages among software developers. When focusing specifically on professional developers, the top programming languages remain the same, with SQL taking second place. For those learning Computer programming to code, the most popular languages are Python, HTML, JavaScript, Java, and C++ 1. This survey data highlights the versatility and widespread use of languages like JavaScript, Python, and SQL. We’ll build a sample Swift UI application that encrypts, stores, and decrypts data. The business logic resides in Kotlin, while platform-specific functionality is implemented in Swift.

Flutter vs React Native in 2025: Which Framework Dominates Cross-Platform Development?

• Kotlin Multiplatform is a game-changer for cross-platform development.
• This means you can write a single codebase that works on both platforms, reducing development time, effort, and potential bugs.
• Building and maintaining separate codebases for iOS and Android apps doubles development effort.
• Please note that although this module is created inside our root project directory, it is not connected to any other part of the project (except for consuming the shared module).
• This codebase contains both an Android app built with Jetpack Compose and an iOS app built with SwiftUI.
• Last year, JetBrains announced the stable release of Kotlin Multiplatform, allowing developers to target platforms like Android, iOS, Web, and Desktop using shared business logic written in Kotlin.
• For remote integration, your project might use the Swift Package Manager (SPM) or the CocoaPods dependency manager to connect the iOS framework from a Kotlin Multiplatform project.

This makes iOS app development using Kotlin a practical choice for startups and enterprises alike. Under the hood, KMP uses the Kotlin compiler to generate platform-specific code. For Android, it compiles to JVM bytecode, while for iOS, it compiles to native code using the LLVM compiler. The shared module uses the kotlinx.coroutines library for concurrency and the kotlinx.serialization library for data serialization. KMP allows you to write code once and run it on multiple platforms, including JVM (Java Virtual Machine), JS (JavaScript), and Native (for platforms like iOS, Linux, and macOS).

• The library ecosystem is rapidly growing; there are now around 2,500 Kotlin Multiplatform libraries available.
• By leveraging these insights, teams can achieve a more seamless integration between Kotlin and Swift, ultimately leading to more efficient and enjoyable development processes.
• Click on it to see a list of potential architectural options, and choose Any iOS Simulator SDK.
• We have prepared a number of example projects that demonstrate Compose Multiplatform on iOS and its other targets.
• Each of these roles may prioritize different app development languages.
• You can check the progress of the gradle sync in the   tab at the bottom of Android Studio to see the sync’s progress.

Quality Gates and Tooling for KMP Codebases

• The 1.8.0 release introduces further improvements to interop with SwiftUI and UIKit, allowing you to seamlessly embed Compose in an existing app or incorporate native views into a Compose screen.
• For example, we’ll use SQLDelight for databases or Ktor for network calls.
• This includes implementing drag-and-drop support, improving text input and rendering, and ensuring interoperability with HTML page contents.
• In other words, even when you share UI code, you’re not compromising on the fluidity or responsiveness of the app.
• Next time you implement a feature across your app’s various platforms, use KMP to write the business logic, deploy it to each platform, and program the UIs natively.
• Essentially, Compose Multiplatform functions as a dedicated client, following a similar approach to Android’s Jetpack Compose UI, and is built on top of the existing Compose compiler and runtime system.

This template serves as a starting point for developers looking to create cross-platform projects with shared business logic and UI components, making it easier to get started with cross-platform development. Cross-platform solutions, such as React Native, or Flutter, streamline this process by allowing developers to write a single codebase that works on both platforms. This approach is especially beneficial for startups aiming to launch their products on multiple platforms quickly and efficiently. It helps reduce development time, lower costs, and accelerate time to market, enabling teams to focus on scaling and iterating the product rapidly. Kotlin Multiplatform enables you to write shared code for logic that is common across different platforms like Android, iOS, and web while allowing platform-specific implementations for native features.

How does Kotlin compare to Swift?

You can now extract the business logic code to the Kotlin Multiplatform shared module and make it platform-independent. Kotlin/Native comes with a set of pre-imported system frameworks; it’s also possible to import an existing framework and use it from Kotlin. In this tutorial, you’ll learn how to create your own framework and use Kotlin/Native code from Swift/Objective-C applications on macOS and iOS.

These updates bring Compose Multiplatform for the web one step closer to providing a polished, production-ready experience. You can learn more about our vision and plans Senior iOS developer job for Kotlin web development in the upcoming post “The Present and Future of Kotlin for the Web.” Stay tuned. In that case, it might not be apparent that the above Kotlin source code for the iOS implementation is based on Objective-C APIs, not Swift APIs. (“NSDate” might give this away.) This means that the Kotlin code you’re writing for iOS is effectively “Objective-C-ified Kotlin” and lacks many pleasantries that the Swift language provides. There are also some gray areas you might not realize are platform-dependent, such as networking APIs, accessing the application bundle, or file URLs, to name a few. The first step in determining where to put your code is to understand if your code is platform-dependent or not.

We’re a place where coders share, stay up-to-date and grow their careers. In production this copy operation is not cheap, and especially with the default methods that the KMP exposes for KotlinByteArray, like get(i), set(i, value). We will consider alternatives in the follow up article iOS String to Kotlin ByteArray Performance Analysis . The main idea of the library is accepting the data, perform a provided crypto operation, and store the value in the provided store.