> ## 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.

# Engines & Models

> Available speech-to-text engines and models on Telnyx — Deepgram, Telnyx native, Google, Azure, xAI, AssemblyAI, Speechmatics, Soniox — selectable via query parameters.

Set via `transcription_engine` and `model` query parameters.

## Engines

| Engine           | Default model                    | Other models     | Notes                                                                       |
| ---------------- | -------------------------------- | ---------------- | --------------------------------------------------------------------------- |
| **Deepgram**     | `nova-3`                         | `nova-2`, `flux` | Default engine. Broadest format support.                                    |
| **Telnyx**       | `openai/whisper-tiny`            | —                | On-network, lightweight                                                     |
| **Google**       | `latest_long`                    | —                | Multilingual, long-form                                                     |
| **Azure**        | `azure/fast`                     | —                | Broad language/accent coverage                                              |
| **xAI**          | `xai/grok-stt`                   | —                | Grok STT for real-time transcription                                        |
| **AssemblyAI**   | `assemblyai/universal-streaming` | —                | Universal-Streaming for low-latency voice agents                            |
| **Speechmatics** | `speechmatics/standard`          | —                | High-accuracy real-time transcription with multilingual and bilingual packs |
| **Soniox**       | `soniox/stt-rt-v4`               | —                | Real-time transcription with automatic language detection                   |

## Flux Model

Deepgram's lowest-latency model with built-in [end-of-turn detection](/docs/voice/stt/websocket-streaming/parameters/end-of-turn). Designed for real-time voice agents. See [Audio Formats](/docs/voice/stt/websocket-streaming/parameters/audio-formats) for supported formats.