This Skip framework is available at, which can be checked out and tested with skip test once Skip is installed.


Model object observation for Skip apps.


SkipModel vends the skip.model Kotlin package. This package contains Observable and ObservableObject interfaces, representing the two core protocols that SwiftUI uses to observe changes to model objects.


SkipLib depends on the skip transpiler plugin and the SkipLib package.

SkipModel is part of the core SkipStack and is not intended to be imported directly. The transpiler includes import skip.model.* in generated Kotlin for any Swift source that imports the Combine, Observation, or SwiftUI frameworks.


From the Observation package, SkipModel supports the @Observable and @ObservationIgnored macros.

From Combine, SkipModel supports the ObservableObject protocol and @Published property wrapper.

Most of Skip’s model support is implemented directly in the Skip transpiler. In fact, SkipModel itself contains only empty Observable and ObservableObject marker protocols. These marker protocols are are sufficient for the Skip transpiler to recognize your observable types. When generating their corresponding Kotlin classes, the transpiler then adds the necessary code so that their state can be tracked by the Compose runtime.

Note that other than recognizing the ObservableObject and @Published markers, SkipModel does not support the Combine API.


We welcome contributions to SkipModel. The Skip product documentation includes helpful instructions and tips on local Skip library development.

There are no immediate plans to support additional Combine or Observation module API, but all forms of contributions are considered. That includes test cases, comments, and documentation. When submitting code, please include unit tests in your PR.