What You Can Share in Kotlin Multiplatform (And What You Cannot)

Kotlin Multiplatform, or KMP, is powerful. But it is also misunderstood. Many Android developers assume KMP means write once, run everywhere. That assumption creates confusion, especially around iOS and macOS builds.

What You Can Share in KMP

KMP works best when used for shared logic and core layers.

Shared Code That Works Well

You can safely share:

• Business logic
• Domain models
• Use cases
• Validation logic
• Networking logic
• Data parsing
• State handling
• Repositories

This shared code lives inside the shared/common module and is written once in Kotlin.

What You Can Build on Windows

If you are developing on Windows, here is what works smoothly:

• Writing shared KMP code
• Building Android apps
• Running Desktop apps
• Running Web apps

For many Android developers, this already covers daily development needs.

What You Cannot Build on Windows

This is the most misunderstood part. On Windows, you cannot:

• Build iOS apps
• Build macOS apps
• Run Xcode-based builds

Apple platforms require macOS. There is no production workaround for this. You can still write shared logic on Windows, but final builds must run on a Mac.

UI Sharing: The Realistic View

UI sharing is where expectations must stay realistic.

• Android UI remains Android
• iOS UI remains iOS
• Compose Multiplatform works well for Desktop and Web
• iOS UI sharing is still evolving

• For production apps, most teams:

• Share logic
• Keep platform-specific UI

• This approach is stable and future-proof.

• Should Android Developers Use KMP?

Yes.

If you are an Android developer:

• You reduce duplicate logic
• Your Kotlin skills stay relevant
• iOS teams benefit from shared logic
• Codebases become easier to maintain

KMP works best when boundaries are clear.

Final Thoughts

Kotlin Multiplatform is not magic. But it is practical when used correctly. Share:

• Logic
• Rules
• Data

Do not expect:

• iOS builds on Windows
• One UI for every platform

Clear expectations make KMP a strong long-term choice.

If you want more clear and honest KMP guidance, keep following Coding Reel. No hype. Just facts.