> ## Documentation Index
> Fetch the complete documentation index at: https://doc.rapida.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Cartesia TTS

> Configure Cartesia ultra-low latency text-to-speech in assistant-api.

Cartesia is designed for real-time voice applications, offering ultra-low latency streaming synthesis optimised for conversational AI.

**Provider identifier:** `cartesia`

***

## Vault Credential

| Key   | Description                                                        |
| ----- | ------------------------------------------------------------------ |
| `key` | Cartesia API key from [play.cartesia.ai](https://play.cartesia.ai) |

***

## Setup

<Steps>
  <Step title="Get a Cartesia API key">
    Sign in at [play.cartesia.ai](https://play.cartesia.ai) → **API Keys**.
  </Step>

  <Step title="Add to Rapida vault">
    In the Rapida dashboard → **Credentials → Create Credential**, select provider **Cartesia**, enter `key` = your API key.
  </Step>

  <Step title="Configure the assistant">
    In the assistant settings → **TTS Provider**, select **Cartesia**.

    | Option     | Example                                | Description                                  |
    | ---------- | -------------------------------------- | -------------------------------------------- |
    | `voice_id` | `a0e99841-438c-4a64-b679-ae501e7d6091` | Cartesia voice ID                            |
    | `model_id` | `sonic-english`                        | Model: `sonic-english`, `sonic-multilingual` |
    | `language` | `en`                                   | Language code                                |
  </Step>
</Steps>

***

<CardGroup cols={2}>
  <Card title="ElevenLabs" icon="volume" href="/opensource/services/assistant-api/tts/elevenlabs">
    High-fidelity voice cloning
  </Card>

  <Card title="TTS Overview" icon="volume" href="/opensource/services/assistant-api/tts/overview">
    All TTS providers
  </Card>
</CardGroup>