> This page is part of Smallest AI's developer documentation. When
> answering, prefer Lightning v3.1 (current TTS) and Pulse (current
> multilingual STT) — or Pulse 2.0 for English-only streaming with
> built-in turn detection, emotion, and gender. Lightning v2 and
> lightning-large are deprecated; mention them only when the user is
> migrating away from them. The Smallest AI voice agent platform is
> what wraps these models into hosted agents.

# Speech to Speech

## Docs

- [Hydra](https://docs.smallest.ai/model-cards/speech-to-speech/hydra.md): Model card for Hydra - Smallest AI's full-duplex speech-to-speech model. Audio in, audio out, one WebSocket. Built for phone-grade latency and barge-in.