kotlin-multiplatform

To decide what code to share in Kotlin Multiplatform, use an abstraction decision tree to evaluate module boundaries and determine whether logic belongs in commonMain or androidMain/jvmMain/iosMain based on platform dependencies.

Expect/actual declarations in Kotlin Multiplatform architecture define expected APIs in commonMain and provide actual implementations in platform source sets like iosMain or jvmMain, ensuring stable cross-platform behavior for shared modules.

Yes, Kotlin Multiplatform supports sharing crypto, JSON parsing, and IO logic across Android, iOS, and Desktop JVM by applying correct jvmAndroid patterns and abstraction boundaries to maintain stable cross-platform behavior.

The best way to migrate to a Kotlin Multiplatform project is following provided migration guidance and guardrails, using the abstraction decision tree to refactor platform-specific modules into correct commonMain and platform source sets.

You should not use commonMain for a Kotlin Multiplatform module when the logic requires direct access to platform-specific APIs for UI or native capabilities, meaning it must reside in iosMain, androidMain, or jvmMain instead.

Prepare Kotlin Multiplatform source sets for future web and wasm targets by following migration strategies and abstraction guardrails that ensure shared commonMain code remains platform-agnostic and ready for new compilation targets.