Introduction: Sudoku sample app for Android, Web and iOS using Koltin/JVM + Kotlin/JS + Kotlin/Native
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This is not an official Google product

Sudoku Playground is a work-in-progress sudoku game app for Android, Web (JS) and iOS.

It's a hobby project to learn about Android APIs, libraries and best practices. It contains a functional sudoku board generator and solver, as well as UI so that you can actually play a sudoku board from start to finish.

This project is also an exploration of business logic code sharing between platforms using Kotlin Multiplatform.

At the same time, this app is not meant to showcase the best-in-class sudoku algorithms - the ones implemented are good enough for this sample.

Android development

Some tech you can find inside:

  • Entirely written in Kotlin (+ some Swift for iOS UI)
  • The sudoku generator/solver is a pure Kotlin common module, included from the Android, iOS and JavaScript frontends
  • Uses Architecture Components: ViewModels and LiveData
  • Uses Data Binding to connect views to ViewModels (and observes LiveData!)
  • Uses dagger-android for dependency injection
  • Uses Android App Links to open deep links directly into the app, and also provides an Instant App version from the same project

    To showcase the power of Kotlin multiplatform, some additional considerations were made:

  • Sudoku boards are generated using a deterministic algorithm shared between frontends, i.e. given a pseudo-random number generator (PRNG) initialized with the same seed, you will always get the same board
  • Android app supports sharing and opening deep links containing a seed number used to initialize the board (e.g.
  • The website counterpart to the Android app is hosted under the same URLs and will show the same board when opened in a web browser, thanks to the shared, deterministic algorithm

Development setup

You require the latest Android Studio 3.4 (or newer) to be able to build the app.


If you've found an error in this sample, please file an issue.

Patches are encouraged, and may be submitted by forking this project and submitting a pull request. Since this project is still in its very early stages, if your change is substantial, please raise an issue first to discuss it.


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