- Built a 3D avatar platform from scratch with SceneKit, RealityKit and Metal — stable 60 FPS.
- Rebuilt core parts of the social platform — chat, stories and calls — strengthening UX consistency and scalability.
- Shipped audio/video calling infrastructure on LiveKit, CallKit and WebSockets with low-latency stability.
- Migrated networking to Swift Concurrency & async/await, simplifying asynchronous code.
- Cut app startup time 8s → 4s through rendering and concurrency optimizations.



