{"slug": "build-a-voicemail-generator-with-elevenlabs-api", "title": "Build a Voicemail Generator with ElevenLabs API", "summary": "A developer published a walkthrough for building a voicemail generator that uses the ElevenLabs text-to-speech API to synthesize personalized greetings and clone custom voices from short audio samples. The tutorial wraps the TTS and voice-cloning endpoints in a Flask service exposing a single /voicemail endpoint that accepts a caller name, message, and optional voice ID and returns generated audio.", "body_md": "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.\n\nThe 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.\n\n| Item | Description | \n|---|---|\n| Python 3.8+ | For the example code | \n| `pip` | To install dependencies | \n| ElevenLabs API key | Sign up at [https://try.elevenlabs.io/kr07zfuqn1bp](https://try.elevenlabs.io/kr07zfuqn1bp) | \n| Basic knowledge of Flask | We’ll expose a simple HTTP endpoint | \n\n**Tip**: If you’re new to ElevenLabs, the link above gives you a free trial with credit to test the API.\n\nElevenLabs 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.\n\nStore it in an environment variable for security:\n\n```\nexport ELEVENLABS_API_KEY=\"sk_your_key_here\"\ncurl -X POST \"https://api.elevenlabs.io/v1/text-to-speech/eleven_monolingual_v1\" \\\n  -H \"xi-api-key: $ELEVENLABS_API_KEY\" \\\n  -H \"Content-Type: application/json\" \\\n  -d '{\"text\":\"Hello, this is a test.\"}'\n```\n\nYou should receive an audio stream in the response body. Great! You’re ready to embed this into an app.\n\nElevenLabs 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.\n\n``` python\nimport requests\nimport os\n\nAPI_KEY = os.getenv(\"ELEVENLABS_API_KEY\")\nBASE_URL = \"https://api.elevenlabs.io/v1\"\n\ndef clone_voice(audio_file_path, voice_name):\n    \"\"\"Clone a new voice from an audio sample.\"\"\"\n    headers = {\n        \"xi-api-key\": API_KEY,\n        \"Content-Type\": \"application/json\",\n    }\n    data = {\n        \"voice_name\": voice_name,\n        \"audio_url\": None,  # We'll upload the file directly\n    }\n    # Upload the audio file first\n    with open(audio_file_path, \"rb\") as f:\n        files = {\"file\": f}\n        upload_resp = requests.post(f\"{BASE_URL}/audio/upload\", files=files, headers={\"xi-api-key\": API_KEY})\n    upload_resp.raise_for_status()\n    audio_url = upload_resp.json()[\"url\"]\n\n    # Create the voice\n    data[\"audio_url\"] = audio_url\n    resp = requests.post(f\"{BASE_URL}/voices\", json=data, headers=headers)\n    resp.raise_for_status()\n    return resp.json()[\"voice_id\"]\n```\n\n**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.\n\nWe’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:\n\n`bytes` stream.\n\n``` python\nfrom flask import Flask, request, send_file, jsonify\nimport requests\nimport os\nimport io\n\napp = Flask(__name__)\n\nELEVENLABS_API_KEY = os.getenv(\"ELEVENLABS_API_KEY\")\nBASE_URL = \"https://api.elevenlabs.io/v1\"\n\ndef synthesize_text(text, voice_id):\n    headers = {\n        \"xi-api-key\": ELEVENLABS_API_KEY,\n        \"Content-Type\": \"application/json\",\n    }\n    payload = {\n        \"text\": text,\n        \"voice_id\": voice_id,\n        \"model_id\": \"eleven_monolingual_v1\",\n    }\n    resp = requests.post(f\"{BASE_URL}/text-to-speech/{voice_id}\", json=payload, headers=headers, stream=True)\n    resp.raise_for_status()\n    return resp.content\n\n@app.route(\"/voicemail\", methods=[\"POST\"])\ndef voicemail():\n    data = request.json\n    caller = data.get(\"caller_name\", \"Someone\")\n    message = data.get(\"message\", \"I couldn't answer your call.\")\n    voice_id = data.get(\"voice_id\")\n\n    if not voice_id:\n        # Fallback to a default voice\n        voice_id = \"EXkTlv5x2jJ5fK8V2i9F\"  # Replace with your own default voice ID\n\n    full_text = f\"Hi, this is {caller}. {message}\"\n    audio_bytes = synthesize_text(full_text, voice_id)\n\n    return send_file(\n        io.BytesIO(audio_bytes),\n        mimetype=\"audio/mpeg\",\n        as_attachment=True,\n        download_name=\"voicemail.mp3\",\n    )\n\nif __name__ == \"__main__\":\n    app.run(debug=True)\n```\n\n`POST /voicemail`\n\n```\n  {\n    \"caller_name\": \"Alice\",\n    \"message\": \"Sorry I missed your call, please leave a message after the tone.\",\n    \"voice_id\": \"EXkTlv5x2jJ5fK8V2i9F\"\n  }\n```\n\n`voicemail.mp3`.\nThe `synthesize_text` helper streams the audio directly from ElevenLabs, so you’re not holding large buffers in memory.\n\nNow that we have the core logic, let’s test the service locally.\n\n```\n# Start the server\npython app.py\n```\n\nIn another terminal, call the endpoint:\n\n```\ncurl -X POST \"http://localhost:5000/voicemail\" \\\n  -H \"Content-Type: application/json\" \\\n  -d '{\"caller_name\":\"Bob\",\"message\":\"Please leave a message after the beep.\"}' \\\n  -o voicemail.mp3\n```\n\nOpen `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.\n\n`/voicemail` endpoint into a Twilio webhook so that when a call is missed, Twilio automatically plays the generated audio.\nElevenLabs’ 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.\n\nIf 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!", "url": "https://wpnews.pro/news/build-a-voicemail-generator-with-elevenlabs-api", "canonical_source": "https://dev.to/voice_developer/build-a-voicemail-generator-with-elevenlabs-api-507c", "published_at": "2026-10-06 02:11:07+00:00", "updated_at": "2026-10-06 02:17:27.395745+00:00", "lang": "en", "topics": ["ai-tools", "generative-ai", "natural-language-processing", "developer-tools"], "entities": ["ElevenLabs", "Flask", "Python"], "also_reported_by": [], "alternates": {"html": "https://wpnews.pro/news/build-a-voicemail-generator-with-elevenlabs-api", "markdown": "https://wpnews.pro/news/build-a-voicemail-generator-with-elevenlabs-api.md", "text": "https://wpnews.pro/news/build-a-voicemail-generator-with-elevenlabs-api.txt", "jsonld": "https://wpnews.pro/news/build-a-voicemail-generator-with-elevenlabs-api.jsonld"}}