Welcome to the future of mobile app development.

Kotlin Multiplatform Mobile allows developers to save time by writing the business logic for their iOS and Android apps just once, in pure Kotlin. Kotlin compiles an embedded framework that is shared between iOS and Android apps. Developers can now write and reuse code that is shared across platforms.

In this course we create a GraphQL server and shared repository in pure Kotlin. The course code covers the Ktor GraphQL server, and client-side shared repository. The final chapter provides an overview of Jetpack Compose and SwiftUI.

What is KMM?

Kotlin Multiplatform, or KMM allows developers to create cross-platform mobile applications using shared business logic. Under the hood, Kotlin compiles a shared framework that is embedded with native iOS and Android applications.

KMM is designed to handle core business logic in Kotlin such as client-side networking, caching and persistence.

In short, KMM will handle any logic that does not involve displaying data. The benefit of this approach is that you can reuse code, save time, and still leverage the latest iOS and Android technologies.

Why KMM?

Pros

• Native performance and flexibility, along with code reusability.

• Platform-specific code that *just works*.

• No restrictions on your app's UI, so you can build with SwiftUI, Jetpack Compose, etc.

Cons

• There is a learning curve if you have little to no experience with Kotlin.

• Multiplatform projects are currently in alpha. Language features and tooling may change in future Kotlin versions.

Installation

In this course, we will be using two different IDEs:

1. IntelliJ IDEA

2. Android Studio Preview (Arctic Fox).

In order to develop iOS applications, you will need a computer running Mac OS and Xcode 12+. Xcode is not required for this course. The code we write is pure Kotlin, and you have the option to write Swift for the final project.

Ready? Let's get started.