Ultravox plugin guide | LiveKit Documentation

Available in

Python

Overview

The Ultravox Realtime API combines STT, LLM, and TTS into a single connection. Use LiveKit's Ultravox plugin with this plugin to create an agent quickly without needing to wire up multiple providers.

Quick reference

This section includes a basic usage example and some reference material. For links to more detailed documentation, see Additional resources.

Installation

Install the Ultravox plugin:

uv add "livekit-agents[ultravox]"

Authentication

The Ultravox plugin requires an API key which can be accessed on the Ultravox console's Settings page. Set ULTRAVOX_API_KEY as a variable in your .env file.

Usage

Use Ultravox in an AgentSession. For example, you can use it in the Voice AI quickstart.

from livekit.plugins import ultravox

session = AgentSession(
   llm=ultravox.realtime.RealtimeModel(),
)

Logging

You can optionally enable debug logs (disabled by default):

LK_ULTRAVOX_DEBUG=true uv run src/agent.py dev

Parameters

This section describes some of the available parameters. For a complete reference of all available parameters, see the plugin reference.

voicestrRequiredDefault: Mark

Ultravox voice to use from the available voices.

time_exceeded_messagestrOptional

Message to play when max duration is reached.

Additional resources

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

Python package

The livekit-plugins-ultravox package on PyPI.

Plugin reference

Reference for the Ultravox plugin.

GitHub repo

View the source or contribute to the LiveKit Ultravox plugin.

Ultravox Realtime docs

Ultravox documentation.

Voice AI quickstart

Get started with LiveKit Agents and Ultravox.