DuelSync
Two phones. One referee. Sixty ways to lose gracefully.
An offline challenge game that turns two phones — or one shared phone — into a competitive game controller and impartial referee.
Worth knowing
Camera, motion, microphone and two-phone gameplay exist at the infrastructure level and are excluded from verified ranked play until physical-device testing completes.
Screenshots
Captured from the debug build running on an Android 14 emulator.
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What DuelSync is
DuelSync is a party game with an engineering heart: a reusable challenge engine, a versioned match protocol and a catalogue of 60 data-driven challenges spanning reaction, tapping, memory, logic, word play, drawing and hidden-timer duels. Play pass-and-play on one phone today; the Nearby point-to-point transport for true two-phone matches is built and being verified on physical devices. On-device ML Kit face analysis, sensors and audio are wired at the infrastructure level — and stay out of ranked play until they earn their way in through testing.
What it does
- 60 data-driven challenges across seven duel types
- Pass-and-play on one phone or point-to-point on two
- Versioned match protocol with an impartial referee
- On-device ML Kit face challenges — nothing uploaded
- Capability-aware challenge library
- Fully offline with no accounts
The referee is incorruptible
Every DuelSync challenge runs on a deterministic engine with a versioned protocol, so neither phone — and neither sibling — can argue with the result.
Getting DuelSync
DuelSync is still in development and is not distributed yet. It is roughly 80% of the way to a first public release.
At a glance
- Status
- Beta
- Runs on
- Android
- Offline use
- Works offline
- Package
- com.duelsync
- Last updated
Privacy
DuelSync plays offline. Matches travel phone-to-phone over Nearby connections; camera and microphone challenges are processed on-device and nothing is uploaded.
Permissions
- Bluetooth and Nearby devices
- Links two phones directly for head-to-head matches. No internet involved.
- Location
- Required by Android for Bluetooth scanning on older versions. DuelSync does not track where you are.
- Camera
- Powers face-analysis party challenges. Processing is on-device via ML Kit.
- Microphone
- Powers sound-based challenges. Audio is analysed on the device.
- Vibration
- Haptic feedback during duels.
Technical details
Technical details
Built with
How it is put together
- Two phones pair directly over Nearby — point to point, with no server between them.
- Face analysis runs on-device through ML Kit; 60 challenges are data, not hard-coded screens.
Development workflow
Built through Claude Code.
Accessibility in the app
- Capability-aware library hides challenges a device cannot run fairly
- Challenge rules readable before every round
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