Solitaire & FreeCell (KMP)
Built for Batteries Included, LLC: one Kotlin codebase ships the same game to Android, iOS, web, and desktop JVM—shared rules and tests in one module, with a lightweight KorGE client on top.
At Batteries Included, LLC I built this Kotlin Multiplatform card-game stack so Solitaire and FreeCell rules live in a shared module with common tests, while a small real-time KorGE shell runs those rules on each platform: Android, desktop JVM, web, and iOS. The focus is consistent domain code, per-platform input and rendering, and multi-target Gradle packaging— a foundation the company can ship and extend, not a throwaway demo.
Company
Role
Kotlin in the shared layer
Automated tests on shared rules
Figures measured 2026-08-22. Tests live in the shared module’s commonTest source set (Gradle/KMP)—same tests back JVM, Android, and other linked targets. Breakdown and counting notes are in the repo README.
CI status
What lives in shared code
- Models for cards, piles, overall game state, and which variant rules apply
- Player actions, validation, and accepted or rejected move results
- Solitaire and FreeCell rule sets plus shared rule plumbing
- Session management, deterministic state updates, undo and redo, and game factories
- Read models so UIs can render without reaching into rule internals
Why Kotlin Multiplatform fits this project
- One implementation of the rules, shipped to web, desktop JVM, Android, and iOS from the same project
- Tests in common source exercise the same paths every client links against
- A clear boundary: KorGE stays in the client module; the domain stays plain Kotlin
- A small real-time client doubles as a stress test for shared state and multi-target builds