> ## Documentation Index
> Fetch the complete documentation index at: https://penseapp.vercel.app/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Text to Speech

> Supported TTS providers in Calibrate

| Provider        | Model                    | Default Voice | Website                                                     |
| --------------- | ------------------------ | ------------- | ----------------------------------------------------------- |
| **Cartesia**    | sonic-3                  | Riya          | [cartesia.ai](https://cartesia.ai)                          |
| **OpenAI**      | gpt-4o-mini-tts          | coral         | [openai.com](https://openai.com)                            |
| **Groq**        | orpheus                  | troy          | [groq.com](https://groq.com)                                |
| **Google**      | chirp\_3                 | Charon        | [cloud.google.com](https://cloud.google.com/text-to-speech) |
| **Gemini**      | gemini-3.1-flash-tts     | Kore          | [ai.google.dev](https://ai.google.dev/gemini-api)           |
| **ElevenLabs**  | eleven\_multilingual\_v2 | Krishna       | [elevenlabs.io](https://elevenlabs.io)                      |
| **Sarvam**      | bulbul:v3-beta           | aditya        | [sarvam.ai](https://sarvam.ai)                              |
| **Smallest AI** | lightning                | aditi         | [smallest.ai](https://smallest.ai)                          |

Some providers use different models for specific languages:

| Provider       | Language | Model      |
| -------------- | -------- | ---------- |
| **Google**     | Sindhi   | gemini     |
| **ElevenLabs** | Sindhi   | eleven\_v3 |

## Configuration

Set the required environment variable for your chosen provider:

```bash theme={null}
# Cartesia
export CARTESIA_API_KEY=your_key

# Google
export GOOGLE_APPLICATION_CREDENTIALS=/path/to/credentials.json

# Gemini (benchmarks only; STT + TTS via the Gemini API)
export GOOGLE_API_KEY=your_key

# OpenAI
export OPENAI_API_KEY=your_key

# ElevenLabs
export ELEVENLABS_API_KEY=your_key

# Sarvam
export SARVAM_API_KEY=your_key

# Groq
export GROQ_API_KEY=your_key

# Smallest
export SMALLEST_API_KEY=your_key
```