Get a superior iOS developer experience in KMP
Use SKIE, a Swift-friendly API Generator for Kotlin Multiplatform
When Swift calls Kotlin through Objective-C, critical Kotlin language features are dropped. SKIE bridges modern types and coroutines in the best way: with real Swift.
Critical features for the KMP iOS developer experience
SKIE is packed with features that make Kotlin Multiplatform frameworks feel like native Swift. We carefully designed each feature to be intuitive, while staying consistent throughout many use-cases.
Direct Linking
The generated Swift is compiled and linked directly to the Xcode Framework. No extra deployment config required.
Flows
Use any Flow as an AsyncSequence from Swift, keeping the element type intact. Safe and smart.
Suspend Interop
Call Kotlin suspend functions the same way as Swift's async functions, with cancelation and background thread support.
Transparent Enums
Kotlin enums are transparently converted to proper Swift enums. This allows for exhaustive operations on the Swift side.
Sealed Hierarchies
Sealed class and sealed interface handling allows you to exhaustively switch on sealed Kotlin hierarchies from Swift.
Default Arguments
Overloaded methods are added to the exposed Swift interface to allow calling methods without specifying each argument.
Kotlin to Swift Code Transformations
SKIE improves interoperability between Kotlin and Swift by generating Swift wrappers for Objective-C headers created by the Kotlin compiler. It recreates features supported by both languages that are lost in the translation from Kotlin to Objective-C to Swift.
Flow Support
Kotlin Flows are automatically and transparently converted to Swift AsyncSequences.
- Proper compile-time checking
- Swift-native ergonomics
- Flow, StateFlow and MutableStateFlow
Suspend Interop
Kotlin suspend functions are converted to Swift's native async functions.
- Cancellation support
- Callable from any thread
- No wrapping necessary
Sealed class wrapped as an enum
Sealed classes are unchanged, but an associated enum is generated, as well as a wrapper function to use in switch statements.
- Exhaustively checked sealed classes
- Similar to enums with associated values
Better APIs are valuable for everybody
Android Developers
Kotlin Multiplatform enables Android developers to write code that can be shared with their iOS colleagues. However, doing so results in a loss of many Kotlin language features even though both Kotlin and Swift support them. That makes it difficult for Android developers to judge what their code will look like from Swift.
With SKIE, Kotlin developers don’t have to worry about these complexities of cross-platform development. Their Kotlin code will retain its modern and expressive features and will seamlessly integrate with Swift. That way, developers can focus on more meaningful and engaging tasks.
Risk Mitigation
Adopting Kotlin Multiplatform can be challenging and introducing a new tool to your team might be daunting. Low entry barrier has been part of SKIE from the beginning.
Comprehensive Testing
We test SKIE against a thousand public KMP libraries along with hundreds of hand-written tests.
Immense Flexibility
No two projects are the same. SKIE has granular configurability, letting your team decide what to enhance.
Made by Touchlab
Touchlab has years of experience with Kotlin Multiplatform in production. We built SKIE to solve our problems, let it solve yours too.