LLM API
CartesiaText to speechReleased June 16, 2026

Cartesia Sonic 3.5

Cartesia Sonic 3.5 turns text into speech for $0.078 per 1K characters on LLM API.

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Cartesia Sonic 3.5 prices on LLM API
Text to speech$0.078/ 1K charactersper 1K characters

Call Cartesia Sonic 3.5

POST /v1/audio/speechSet LLMAPI_KEY to your LLM API key.Speech docs

import os

from openai import OpenAI

client = OpenAI(
    base_url="https://api.llmapi.ai/v1",
    api_key=os.environ["LLMAPI_KEY"],
)

speech = client.audio.speech.create(
    model="sonic-3.5",
    voice="f786b574-daa5-4673-aa0c-cbe3e8534c02",
    input="Hello from LLM API",
)
speech.write_to_file("hello.mp3")

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