Cartesia TTS integration guide

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Chat with a voice assistant built with LiveKit and Cartesia TTS

Overview

Cartesia provides customizable speech synthesis across a number of different languages and produces natural-sounding speech with low latency. You can use the Cartesia TTS plugin for LiveKit Agents to build voice AI applications that sound realistic.

Quick reference

This section includes a brief overview of the Cartesia TTS plugin. For more information, see Additional resources.

Installation

Install the plugin from PyPI:

pip install "livekit-agents[cartesia]~=1.2"

pnpm add @livekit/agents-plugin-cartesia@1.x

Authentication

The Cartesia plugin requires a Cartesia API key.

Set CARTESIA_API_KEY in your .env file.

Usage

Use Cartesia TTS within an AgentSession or as a standalone speech generator. For example, you can use this TTS in the Voice AI quickstart.

from livekit.plugins import cartesia

session = AgentSession(
   tts=cartesia.TTS(
      model="sonic-2",
      voice="f786b574-daa5-4673-aa0c-cbe3e8534c02",
   )
   # ... llm, stt, etc.
)

import * as cartesia from '@livekit/agents-plugin-cartesia';

const session = new voice.AgentSession({
    tts: cartesia.TTS(
        model: "sonic-2",
        voice: "f786b574-daa5-4673-aa0c-cbe3e8534c02",
    ),
    // ... llm, stt, etc.
});

Parameters

This section describes some of the available parameters. See the plugin reference links in the Additional resources section for a complete list of all available parameters.

Customizing pronunciation

Cartesia TTS allows you to customize pronunciation using Speech Synthesis Markup Language (SSML). To learn more, see Specify Custom Pronunciations.

Transcription timing

Cartesia TTS supports aligned transcription forwarding, which improves transcription synchronization in your frontend. Set use_tts_aligned_transcript=True in your AgentSession configuration to enable this feature. To learn more, see the docs.

Additional resources

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

Python Agents

ReferenceGitHubPyPI

Node.js Agents

ReferenceGitHubNPM

Cartesia docs

Cartesia TTS docs.

Voice AI quickstart

Get started with LiveKit Agents and Cartesia TTS.

Cartesia STT

Guide to the Cartesia STT integration with LiveKit Agents.