# Build a Voicemail Generator with ElevenLabs API > Source: > Published: 2026-10-06 02:11:07+00:00 When you’re building a contact‑center or a smart‑home system, the last thing you want is an empty voicemail box. A little voice‑AI can turn a static “no answer” message into a personalized, dynamic greeting that feels like a real person. In this post we’ll walk through how to create a **Voicemail Generator** using the ElevenLabs Text‑to‑Speech (TTS) API. We’ll cover everything from authentication to generating a voice‑cloned message, then bundle it into a simple Flask app that can be called via webhook or a REST endpoint. The result? A lightweight service that lets you generate a voicemail audio file on the fly, using the same high‑quality voices you can clone with ElevenLabs. Let’s dive in. | Item | Description | |---|---| | Python 3.8+ | For the example code | | `pip` | To install dependencies | | ElevenLabs API key | Sign up at [https://try.elevenlabs.io/kr07zfuqn1bp](https://try.elevenlabs.io/kr07zfuqn1bp) | | Basic knowledge of Flask | We’ll expose a simple HTTP endpoint | **Tip**: If you’re new to ElevenLabs, the link above gives you a free trial with credit to test the API. ElevenLabs offers a powerful, low‑latency TTS endpoint that supports voice cloning, speaker embeddings, and a large library of natural‑sounding voices. The API is REST‑based, so you can call it from any language. Store it in an environment variable for security: ``` export ELEVENLABS_API_KEY="sk_your_key_here" curl -X POST "https://api.elevenlabs.io/v1/text-to-speech/eleven_monolingual_v1" \ -H "xi-api-key: $ELEVENLABS_API_KEY" \ -H "Content-Type: application/json" \ -d '{"text":"Hello, this is a test."}' ``` You should receive an audio stream in the response body. Great! You’re ready to embed this into an app. ElevenLabs lets you clone a voice by providing a short audio clip. For a voicemail system, you might want to use a company‑wide voice (e.g., a receptionist) or a custom voice that matches your brand. ``` python import requests import os API_KEY = os.getenv("ELEVENLABS_API_KEY") BASE_URL = "https://api.elevenlabs.io/v1" def clone_voice(audio_file_path, voice_name): """Clone a new voice from an audio sample.""" headers = { "xi-api-key": API_KEY, "Content-Type": "application/json", } data = { "voice_name": voice_name, "audio_url": None, # We'll upload the file directly } # Upload the audio file first with open(audio_file_path, "rb") as f: files = {"file": f} upload_resp = requests.post(f"{BASE_URL}/audio/upload", files=files, headers={"xi-api-key": API_KEY}) upload_resp.raise_for_status() audio_url = upload_resp.json()["url"] # Create the voice data["audio_url"] = audio_url resp = requests.post(f"{BASE_URL}/voices", json=data, headers=headers) resp.raise_for_status() return resp.json()["voice_id"] ``` **Remember**: The cloned voice is stored in your ElevenLabs account and can be reused across calls. You’ll get a `voice_id` that you’ll pass to the TTS endpoint. We’ll create a Flask service with a single endpoint: `/voicemail`. It accepts JSON containing a `caller_name`, a `message`, and an optional `voice_id`. The service will: `bytes` stream. ``` python from flask import Flask, request, send_file, jsonify import requests import os import io app = Flask(__name__) ELEVENLABS_API_KEY = os.getenv("ELEVENLABS_API_KEY") BASE_URL = "https://api.elevenlabs.io/v1" def synthesize_text(text, voice_id): headers = { "xi-api-key": ELEVENLABS_API_KEY, "Content-Type": "application/json", } payload = { "text": text, "voice_id": voice_id, "model_id": "eleven_monolingual_v1", } resp = requests.post(f"{BASE_URL}/text-to-speech/{voice_id}", json=payload, headers=headers, stream=True) resp.raise_for_status() return resp.content @app.route("/voicemail", methods=["POST"]) def voicemail(): data = request.json caller = data.get("caller_name", "Someone") message = data.get("message", "I couldn't answer your call.") voice_id = data.get("voice_id") if not voice_id: # Fallback to a default voice voice_id = "EXkTlv5x2jJ5fK8V2i9F" # Replace with your own default voice ID full_text = f"Hi, this is {caller}. {message}" audio_bytes = synthesize_text(full_text, voice_id) return send_file( io.BytesIO(audio_bytes), mimetype="audio/mpeg", as_attachment=True, download_name="voicemail.mp3", ) if __name__ == "__main__": app.run(debug=True) ``` `POST /voicemail` ``` { "caller_name": "Alice", "message": "Sorry I missed your call, please leave a message after the tone.", "voice_id": "EXkTlv5x2jJ5fK8V2i9F" } ``` `voicemail.mp3`. The `synthesize_text` helper streams the audio directly from ElevenLabs, so you’re not holding large buffers in memory. Now that we have the core logic, let’s test the service locally. ``` # Start the server python app.py ``` In another terminal, call the endpoint: ``` curl -X POST "http://localhost:5000/voicemail" \ -H "Content-Type: application/json" \ -d '{"caller_name":"Bob","message":"Please leave a message after the beep."}' \ -o voicemail.mp3 ``` Open `voicemail.mp3` with your favorite player – you should hear a natural‑sounding greeting. If you want to use a cloned voice, pass the `voice_id` you obtained earlier. `/voicemail` endpoint into a Twilio webhook so that when a call is missed, Twilio automatically plays the generated audio. ElevenLabs’ TTS API gives developers the ability to create high‑quality, personalized voicemails with minimal effort. By cloning a voice and exposing a simple REST endpoint, you can turn any missed call into a brand‑consistent, engaging experience. If you’re ready to give your voicemail system a voice upgrade, grab a free trial and start experimenting today. Sign up here: [https://try.elevenlabs.io/kr07zfuqn1bp](https://try.elevenlabs.io/kr07zfuqn1bp) and let ElevenLabs bring your voicemails to life!