HamdorHamdor

Product design, Android app, Wasm web app, game server and infrastructure

Players use mid-range phones on unstable connections and know the local rules by heart. One game had to work offline with bots and online with fair, authoritative matches, run on three platforms, and stay connected even behind DNS filtering.

We wrote one Kotlin Multiplatform rules engine that runs on the phone (offline bots) and on the server (the authoritative referee for online matches). The UI is Compose, and the same code compiles to Kotlin/Wasm so iPhone and desktop players run it in the browser. A Ktor server over a single WebSocket with ProtoBuf messages makes reconnecting and resuming a match the default.

• 36 games in 5 categories: classics, cards, board, sports and puzzles
• Ranked play with Elo ratings, leaderboards and private rooms by code
• Offline play against bots at several difficulty levels, plus pass-and-play
• Friends, in-match chat, stickers and public chat rooms
• Payments via ZarinPal, Bale wallet, Cafe Bazaar and Myket — no gambling
• Full admin console: live dashboard, match control, shop and revenue reports

1. 01

   Clients

   • Android · Jetpack Compose
   • Web · Kotlin/Wasm PWA
   • iPhone · PWA
2. 02

   Shared core

   • KMP rules engine
   • Bots
   • Protocol · ProtoBuf
3. 03

   Server

   • Ktor 3 · WebSocket
   • Match runtime
   • Admin · Shop · Bale bot
4. 04

   Data & infra

   • PostgreSQL 17
   • Docker Compose
   • Caddy · precompressed assets

• 01One shared rules engine for offline bots and the server referee
• 02A 15 MB Wasm binary ships pre-compressed with brotli to 2.7 MB
• 03The app carries the server address itself, so it connects behind DNS filtering
• 04The Bale bot runs inside the API process with long polling — no webhook, no extra port
• 05Deploys take a pre-deploy backup and roll back automatically when unhealthy

• Kotlin
• Jetpack Compose
• Compose Multiplatform
• Kotlin/Wasm
• Kotlin Multiplatform
• Ktor
• PostgreSQL
• WebSocket + ProtoBuf
• Docker
• Caddy

• One Kotlin codebase for Android, web and iPhone
• Smooth on mid-range phones and weak connections
• A healthy revenue model: cosmetics and a subscription, never gambling