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

# Voice Design API parameters

> Provider differences and generation parameters for the Voice Design API.

## Providers

Set via the `provider` body parameter on `POST /v2/voice_designs`.

|                           | Telnyx (Qwen3TTS)                                                                               | Minimax                                                                                         |
| ------------------------- | ----------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------- |
| **`provider` value**      | `"telnyx"` (default)                                                                            | `"minimax"`                                                                                     |
| **Generation parameters** | Respected                                                                                       | Not supported                                                                                   |
| **Languages**             | Auto, Chinese, English, Japanese, Korean, German, French, Russian, Portuguese, Spanish, Italian | Auto, Chinese, English, Japanese, Korean, German, French, Russian, Portuguese, Spanish, Italian |
| **Prompt interpretation** | Follows prompts closely                                                                         | May interpret differently                                                                       |
| **When to use**           | Fine control over generation, consistent results across iterations                              | Try a different model's interpretation of the same prompt                                       |

## Generation Parameters

Body parameters on `POST /v2/voice_designs`. **Telnyx provider only** — ignored when `provider` is `"minimax"`.

| Body parameter       | Default | Range    | What it does                                                     |
| -------------------- | ------- | -------- | ---------------------------------------------------------------- |
| `temperature`        | 0.9     | 0–2      | Higher = more varied/creative output. Lower = more predictable.  |
| `top_k`              | 50      | 1–1000   | Limits vocabulary at each generation step. Lower = more focused. |
| `top_p`              | 1.0     | 0–1      | Nucleus sampling cutoff. Lower = fewer token choices.            |
| `repetition_penalty` | 1.05    | 1–2      | Reduces repeated patterns in generated audio.                    |
| `max_new_tokens`     | 2048    | 100–4096 | Maximum tokens to generate. Affects output length.               |

<Tip>
  The defaults are a great starting point — you can skip these parameters entirely and get good results. Adjust them later if you want to fine-tune the output.
</Tip>