Kotlin

Kotlin is a modern programming language developed by JetBrains that runs on the JVM, Android, and now cross-compiles to iOS, JavaScript, native desktop, and server environments via Kotlin Multiplatform (KMP). For mobile apps, Kotlin lets you write a single codebase that compiles to both the Android platform (the native host) and iOS (where Kotlin code is compiled to machine code via the Kotlin/Native compiler with interoperability through C-interop). You can take one application, designed for both ecosystems, and publish it in the Play Store and App Store. This saves massive amounts of time and effort that go into developing a mobile app in their native languages (Java/Kotlin for Android, Swift for iOS).

With the powerful Kotlin Multiplatform ecosystem to fall back on, it can make sense to use Kotlin for the business logic, networking, database, and data layer if you want a shared codebase without sacrificing native UI. Kotlin’s design allows Parthenon to make part of the application sharable between platforms, while still being able to access native functionality on a specific platform.

Advantages

Kotlin nearly cuts your development time in half when you are targeting both Apple and Android devices. This is hands down the most cost effective way to roll out a cross-platform mobile app that has the same level of performance and UI seamlessness as native Android/iOS. Additionally, Kotlin is null-safe by design, so you get protection against the #1 cause of mobile crashes without any extra developer costs. The language is interoperable with all existing Java libraries on Android, so you can migrate incrementally — no “all or nothing” rewrite.

When we’re writing your mobile app in Kotlin, a significant portion of your app’s logic lives in a single shared module. That means bug fixes and feature additions usually propagate to both platforms automatically. And JetBrains has been spending a lot of time porting Kotlin to other platforms. In addition to iOS, where it has essentially native interoperability, they’ve also succeeded in porting it to WebAssembly, meaning that we can make an app that runs natively on a web browser as high-performance as an executable on another platform!

Risks

Depending on your app, a shared Kotlin codebase may not have the polish for a fully native user experience on either platform. Games and other graphically intensive apps need access to low level system calls that Kotlin Multiplatform is built on top of but not directly managed by. Apple occasionally changes its Swift/iOS APIs in ways that break Kotlin/Native’s interop layer, and the more Apple-centric the feature you are targeting, the less advantage a Kotlin app will have. In these cases, a fully native app may be the best fit for your project.