diamond9

Early Development — This app is in an early stage of development. Features may be incomplete, change without notice, or contain bugs.

Baseball Coach App for Android

diamond9 helps baseball coaches manage their team during a game — track pitchers, build lineups, and log pitches in real time, all without internet access.

This project is built with AI-assisted development (vibe coding) using Claude Code.

---

Features

• Team management — Create teams, manage rosters with jersey numbers, positions, and birth year
• Game management — Create and manage games per team, with optional start time and home/away flag
• Live pitch tracking — Log Ball, Strike, Foul, HBP, Walk, K per batter with undo support
• Pitcher stats — Batters faced, balls, strikes, strike percentage, innings pitched (IP)
• Batting tracking — Log at-bat results (Hit, Walk, K, HBP, Out) per player per game
• Scoreboard — Inning-by-inning run tracking for both teams (9 innings)
• Game timer — Stopwatch per game with pause/resume, survives app restarts
• Per-game batting stats — AB, H, BB, K, HBP per batter for a single game
• Season stats — Aggregated batting (AB/H/AVG/BB/K) and pitching (BF/P/S%/BB/K/IP) across all games
• Own lineup — Starters and substitutes with substitution tracking
• Opponent lineup — Batting order, bench, and substitutions
• Team export/import — Share rosters as JSON
• Per-game export/import — Share complete game data (lineup, at-bats, pitches, scoreboard) as JSON
• Offline-first — Everything stored locally on device, no internet required
• Multilingual — English and German

Screenshots

Coming soon

Requirements

• Android 8.0 (API 26) or higher

Installation

Download the latest APK from the Releases page and install it on your Android device.

You may need to enable Install from unknown sources in your Android settings.

Build from source

1. Clone the repository
2. Open in Android Studio
3. Run on an emulator or physical device (minSdk 26, targetSdk 35)

./gradlew assembleDebug

Tech stack

• Language: Kotlin
• UI: Jetpack Compose with Material 3
• Database: Room (SQLite)
• Navigation: Compose Navigation

Roadmap

• Season management (group games by season)
• Configurable innings per team (7 / 9 / custom)
• Full database backup/restore (all teams and games)
• RBI tracking
• More translations

License

See LICENSE.

Disclaimer

This app is provided as-is for personal use by baseball coaches.