LiveKit docs › Models › TTS › Additional models › SLNG

---

# SLNG TTS plugin guide

> How to use the SLNG TTS plugin for LiveKit Agents.

Available in:
- [ ] Node.js
- [x] Python

## Overview

[SLNG](https://slng.ai/) is a third-party gateway that proxies TTS requests to underlying providers (such as Deepgram and Rime) through a unified API. The plugin streams synthesized audio over WebSocket and routes requests across regions using a single API key.

### Installation

Install the plugin:

```shell
uv add "livekit-agents[slng]~=1.5"

```

### Authentication

The SLNG plugin requires a SLNG API key. Sign up at [slng.ai](https://slng.ai/) to get one.

Set `SLNG_API_KEY` in your `.env` file.

### Usage

Use SLNG TTS in an `AgentSession` or as a standalone speech generator. For example, you can use this TTS in the [Voice AI quickstart](https://docs.livekit.io/agents/start/voice-ai.md).

```python
from livekit.plugins import slng

session = AgentSession(
   tts=slng.TTS(
      model="deepgram/aura:2",
      voice="aura-2-thalia-en",
   ),
   # ... llm, stt, etc.
)

```

### Parameters

This section describes some of the available parameters. See the [plugin reference](https://docs.livekit.io/reference/python/livekit/plugins/slng/index.html.md) for a complete list of all available parameters.

- **`api_key`** _(string)_ (optional) - Environment: `SLNG_API_KEY`: SLNG API key. Required if the environment variable isn't set.

- **`model`** _(string)_ (optional) - Default: `deepgram/aura:2`: The SLNG model identifier in `<provider>/<model>[:variant]` format. For a list of supported provider and model identifiers, see the [SLNG documentation](https://docs.slng.ai/).

- **`voice`** _(string)_ (optional): The voice identifier to synthesize with. Valid values depend on the selected model and provider. For supported voices, see the [SLNG documentation](https://docs.slng.ai/). When omitted, the gateway selects a provider-appropriate default.

- **`slng_base_url`** _(string)_ (optional) - Default: `api.slng.ai`: The SLNG gateway host. Override this only if you need to use a custom deployment.

- **`region_override`** _(string | list[str])_ (optional): Pin requests to one or more SLNG regions, as a single region code or a priority-ordered list. Sent to the gateway as the `X-Region-Override` header. For the supported region codes, see the [SLNG documentation](https://docs.slng.ai/voice-agents#agent-regions).

- **`language`** _(string)_ (optional) - Default: `en`: Language code for the input text. Supported values depend on the selected model.

- **`speed`** _(float)_ (optional) - Default: `1.0`: Speed multiplier for the generated audio.

## Additional resources

The following resources provide more information about using SLNG with LiveKit Agents.

- **[Python package](https://pypi.org/project/livekit-plugins-slng/)**: The `livekit-plugins-slng` package on PyPI.

- **[Plugin reference](https://docs.livekit.io/reference/python/livekit/plugins/slng/index.html.md)**: Reference for the SLNG plugin.

- **[GitHub repo](https://github.com/livekit/agents/tree/main/livekit-plugins/livekit-plugins-slng)**: View the source or contribute to the LiveKit SLNG plugin.

- **[SLNG docs](https://docs.slng.ai/)**: SLNG's full docs site.

- **[Voice AI quickstart](https://docs.livekit.io/agents/start/voice-ai.md)**: Get started with LiveKit Agents and SLNG.

- **[SLNG STT](https://docs.livekit.io/agents/models/stt/slng.md)**: Guide to the SLNG STT plugin with LiveKit Agents.

---

This document was rendered at 2026-06-07T11:35:25.668Z.
For the latest version of this document, see [https://docs.livekit.io/agents/models/tts/slng.md](https://docs.livekit.io/agents/models/tts/slng.md).

To explore all LiveKit documentation, see [llms.txt](https://docs.livekit.io/llms.txt).