Overall Flow
For one Avatar response: the audio the Avatar should speak is sent to Motion Server, Motion Server generates motion data, AvatarKit plays the audio locally while rendering synchronized lip and body motion, and your app observes the process through state callbacks.
Core Components
AvatarKit Client SDK
The client SDK covers Web, iOS, Android, and Flutter. It renders the Avatar on the client and keeps avatar speech audio and motion data synchronized. Reference: Web | iOS | Android | FlutterMotion Server
Cloud service provided by Spatius.
- Input: avatar speech audio, usually the TTS output from an ASR -> LLM -> TTS pipeline.
- Output: motion data, ~10–15 KB/s, much lower than a video stream.
- Role: provides motion data that AvatarKit uses to animate the Avatar. AvatarKit synchronizes audio and motion data playback, so application developers don’t need to manage it.

