Freelance Flutter / Android / iOS Developer for Audio-Haptics Synchronization

We are seeking an experienced freelance mobile developer to finalize and stabilize a technically advanced Flutter-based audio and haptics synchronization system. The project involves integrating, testing, and polishing existing code for a cross-platform (Android & iOS) app that synchronizes metronome-based audio playback with waveform-based haptic vibration patterns.

Key Requirements:
- Integrate provided Flutter + Android code into a working build.
- Validate and fine-tune audio ↔ haptic synchronization on Android.
- Implement and tune iOS Core Haptics + Audio functionality.
- Handle latency offsets correctly (positive & negative).
- Finalize the Sync Test UI and ensure settings persistence.
- Populate and validate the device test matrix.
- Run basic real-device tests (Android + iOS).

Ideal Skills and Experience:
- Strong expertise in Flutter (Dart) development.
- Native Android (Kotlin) experience with low-latency audio using SoundPool.
- Familiarity with Core Haptics on iOS or willingness to learn.
- Understanding of audio timing, latency, and scheduling.

Deliverables:
- Working Android & iOS builds with stable audio-haptics synchronization.
- Persisted latency calibration settings.
- Clean test-matrix export in CSV format.