pnpm add @cartesia/cartesia-js

import { CartesiaClient } from "@cartesia/cartesia-js";
import process from "node:process"
import fs from "node:fs"

// Set up the client.
const client = new CartesiaClient({ apiKey: process.env.CARTESIA_API_KEY });

// Call the TTS API's bytes endpoint, which returns binary audio data as an ArrayBuffer.
const response = await client.tts.bytes({
    modelId: "sonic-2",
    transcript: "Hello, world!",
    voice: {
        mode: "id",
        id: "694f9389-aac1-45b6-b726-9d9369183238",
    },
    language: "en",
    outputFormat: {
        container: "wav",
        sampleRate: 44100,
        encoding: "pcm_f32le",
    },
});

// Write the response to a file.
fs.writeFileSync("sonic.wav", new Uint8Array(response));