Kotlin Multiplatform Platform Bridges

Use this skill when designing, implementing, or reviewing platform-specific integrations and shared-to-native boundaries in a Kotlin Multiplatform project.

This skill is intentionally strict. Its purpose is to keep platform-specific code at the edges, maximize valid sharing through source-set hierarchy, avoid unnecessary expect/actual, and preserve testable abstractions between shared and native code.

Primary goals

The bridge design should optimize for:

• correct source-set placement
• maximum valid code sharing before introducing platform splits
• clear shared-to-native abstraction boundaries
• minimal and justified expect/actual usage
• platform API access through the least-coupled mechanism
• reuse across similar platforms through intermediate source sets
• testability and replaceability of native integrations
• avoidance of platform/vendor types leaking into shared business logic