ElevenLabs — AI Voice Synthesis & Cloning

Overview

ElevenLabs is a hosted voice platform: text-to-speech, speech-to-text, voice cloning and a managed conversational agent product. You call it with an API key through the official SDKs (elevenlabs on PyPI, @elevenlabs/elevenlabs-js on npm) or plain HTTP. Checked against elevenlabs 2.70.0 (Python, 28 Sep 2026) and the current models page. Two things changed since many tutorials were written: convert_as_stream no longer exists (use text_to_speech.stream), and the old npm package elevenlabs is deprecated in favour of @elevenlabs/elevenlabs-js.

Instructions

Step 1: Install and authenticate

pip install elevenlabs                       # Python
npm install @elevenlabs/elevenlabs-js        # Node.js (the unscoped "elevenlabs" package is deprecated)
export ELEVENLABS_API_KEY="..."              # create it in the dashboard; never commit it

Step 2: Text to speech

import os
from elevenlabs.client import ElevenLabs
from elevenlabs import VoiceSettings

client = ElevenLabs(api_key=os.environ["ELEVENLABS_API_KEY"])

# find a voice id available to your account
for v in client.voices.search(search="narrator").voices:
    print(v.voice_id, v.name)

audio = client.text_to_speech.convert(
    voice_id="JBFqnCBsd6RMkjVDRZzb",
    text="Welcome to Bright Smile Dental. How can I help you today?",
    model_id="eleven_flash_v2_5",
    output_format="mp3_44100_128",
    voice_settings=VoiceSettings(stability=0.6, similarity_boost=0.8, style=0.3, use_speaker_boost=True),
)
with open("greeting.mp3", "wb") as f:
    for chunk in audio:                      # convert() returns an iterator of bytes
        f.write(chunk)

from elevenlabs.play import play plays audio locally (needs mpv/ffmpeg).

Step 3: Streaming

stream = client.text_to_speech.stream(
    voice_id="JBFqnCBsd6RMkjVDRZzb",
    text="Let me check our appointments for next Tuesday.",
    model_id="eleven_flash_v2_5",
    output_format="pcm_24000",               # raw PCM, no decoding for WebRTC or telephony
)
for chunk in stream:
    send_to_speaker(chunk)                   # your audio sink

Other formats include mp3_*, opus_*, ulaw_8000 and alaw_8000 (phone lines).

Step 4: Voice cloning

voice = client.voices.ivc.create(
    name="Dr. Smith",
    description="Calm, authoritative voice for medical explainers",
    files=["samples/dr_smith_01.mp3", "samples/dr_smith_02.mp3"],
)
print(voice.voice_id)

Instant cloning (voices.ivc) takes a few clean samples; professional cloning (voices.pvc) needs much more audio and identity verification in the dashboard. Only clone voices you have consent to use.

Step 5: Voice agents and Node

from elevenlabs.conversational_ai.conversation import Conversation
from elevenlabs.conversational_ai.default_audio_interface import DefaultAudioInterface

conversation = Conversation(client, agent_id=os.environ["ELEVENLABS_AGENT_ID"],
                            requires_auth=True, audio_interface=DefaultAudioInterface())
conversation.start_session()      # runs in the background
conversation.end_session()

The agent itself (prompt, voice, tools) is created in the dashboard or through client.conversational_ai.agents.

import { ElevenLabsClient } from "@elevenlabs/elevenlabs-js";
const client = new ElevenLabsClient();       // reads ELEVENLABS_API_KEY
const audio = await client.textToSpeech.convert("JBFqnCBsd6RMkjVDRZzb", {
  text: "Hello! How can I assist you?",
  modelId: "eleven_flash_v2_5",              // camelCase options in the JS SDK
  outputFormat: "mp3_44100_128",
});

Models (per the models page, Oct 2026)

Model	Use for
eleven_flash_v2_5	lowest latency (~75 ms), 32 languages, half price per character; agents and real-time
eleven_multilingual_v2	stable long-form narration, 29 languages
eleven_v3 and newer v-series (see the models page)	most expressive speech, higher latency, shorter text limits
eleven_turbo_v2_5	deprecated in favour of Flash v2.5

Examples

Example 1: "Read this paragraph aloud and save it as MP3"

Run Step 2 with text set to the paragraph and model_id="eleven_multilingual_v2". Result: greeting.mp3 in the working directory; a 401 means the key is wrong, 402 or quota errors mean the plan's character allowance is used up.

Example 2: "Stream a reply to my phone-call bot"

Use Step 3 with output_format="ulaw_8000" so chunks can go straight to a Twilio media stream. Result: the first bytes arrive within a few hundred milliseconds and play while the rest is generated.

Guidelines

• Billing is per character (credits); cache fixed prompts such as greetings instead of regenerating them.
• Stability around 0.3-0.5 sounds more expressive, 0.7-0.9 stays consistent for agents; not every setting applies to every model.
• Use pronunciation_dictionary_locators for brand names and jargon. <break time="0.5s"/> pauses are supported on some models only; check the model's page.
• Long text: send it in pieces and pass previous_text / next_text so prosody carries across the joins.
• The API key is secret: keep it server-side, and for browsers use a short-lived token or signed URL from your backend.
• Voice IDs and the shared voice library change; look voices up with voices.search rather than hard-coding IDs from old tutorials.