# Nemotron VoiceChat 11B

A full-duplex voice model that listens while it speaks. Stream audio in and receive speech, plus transcripts of both sides of the conversation. In public beta.

Model ID `nemotron-voicechat`

[Open in Playground](https://api.dotwave.ai/dashboard?model=nemotron-voicechat) · [Model source](https://huggingface.co/nvidia/NVIDIA-NemotronLabs-VoiceChat-11B)

- **Price**: $0.005 / minute (Introductory price, billed while the session is open)
- **Modality**: Speech to speech (Full duplex)
- **Language**: English (en-US)
- **Session limit**: 120 seconds
- **Status**: Public beta (May change before general availability)

## Use this model

Set `DOTWAVE_API_KEY` on your server, then open and configure a session. See the guides below for audio capture, playback, and transcripts.

```python
import asyncio, json, os
import websockets

LIVE_URL = "wss://api.dotwave.ai/v1/live/sessions"

async def main():
    async with websockets.connect(
        LIVE_URL,
        additional_headers={"Authorization": f"Bearer {os.environ['DOTWAVE_API_KEY']}"},
    ) as ws:
        # session.start must be the first message, or the socket refuses it.
        await ws.send(json.dumps({
            "type": "session.start",
            "session": {
                "model": "nemotron-voicechat",
                "audio": {
                    "input": {
                        "format": {"type": "audio/pcm", "rate": 24000}
                    },
                    "output": {
                        "format": {"type": "audio/pcm", "rate": 24000},
                        "encoding": "base64",
                    },
                },
            },
        }))
        # Send session.input_audio.append and handle
        # session.output_audio.delta events here.

asyncio.run(main())
```

```typescript
import WebSocket from 'ws';

const ws = new WebSocket('wss://api.dotwave.ai/v1/live/sessions', {
  headers: { Authorization: `Bearer ${process.env.DOTWAVE_API_KEY}` },
});

// session.start must be the first message, or the socket refuses it.
ws.on('open', () => {
  ws.send(JSON.stringify({
    type: 'session.start',
    session: {
      model: 'nemotron-voicechat',
      audio: {
        input: { format: { type: 'audio/pcm', rate: 24000 } },
        output: {
          format: { type: 'audio/pcm', rate: 24000 },
          encoding: 'base64',
        },
      },
    },
  }));
});

ws.on('message', raw => {
  const event = JSON.parse(raw.toString());
  if (event.type === 'session.output_audio.delta') {
    playPcm24k(Buffer.from(event.delta, 'base64'));
  }
});
```

```bash
curl https://api.dotwave.ai/v1/live/client_secrets \
  -H "Authorization: Bearer $DOTWAVE_API_KEY" \
  -H "Content-Type: application/json" \
  --data '{
    "expires_after": {
      "anchor": "created_at",
      "seconds": 60
    },
    "session": {
      "type": "live",
      "model": "nemotron-voicechat",
      "audio": {
        "input": {
          "format": {"type": "audio/pcm", "rate": 24000}
        },
        "output": {
          "format": {"type": "audio/pcm", "rate": 24000},
          "encoding": "base64"
        }
      }
    }
  }'
```

[Live API](https://dotwave.ai/docs/live/) · [Python guide](https://dotwave.ai/docs/guides/python/) · [TypeScript guide](https://dotwave.ai/docs/guides/typescript/)

## Specifications

- **Author**: NVIDIA
- **Parameters**: 11B
- **Input**: Audio
- **Output**: Audio and transcripts
- **Interaction**: Full-duplex conversation
- **Access**: [Live API](https://dotwave.ai/docs/live/)

## Limits

Sessions are capped at 120 seconds. VoiceChat uses its built-in persona and speaks in its one voice, `aria`; a `session.start` naming any other voice is refused. Custom instructions, text input, and tools are not supported.

[API reference](https://dotwave.ai/docs/api/)