Webhooks

Overview

Webhooks allow ElevenLabs to send real-time notifications to your application when certain events occur. This is useful for:

Receiving notifications when audio generation is complete
Tracking usage and billing events
Monitoring voice cloning progress
Staying informed about account changes

Setting Up Webhooks

Configure Your Endpoint

First, create an endpoint in your application to receive webhook events:

from flask import Flask, request
from elevenlabs import ElevenLabs, BadRequestError

app = Flask(__name__)
client = ElevenLabs(api_key="YOUR_API_KEY")

@app.route("/webhook", methods=["POST"])
def handle_webhook():
    # Get the raw body and signature
    raw_body = request.get_data(as_text=True)
    signature = request.headers.get("elevenlabs-signature")
    
    try:
        # Verify and construct the event
        event = client.webhooks.construct_event(
            rawBody=raw_body,
            sig_header=signature,
            secret="your_webhook_secret"
        )
        
        # Process the event
        print(f"Received event: {event}")
        
        return {"success": True}, 200
    except BadRequestError as e:
        print(f"Webhook verification failed: {e.body.error}")
        return {"error": "Invalid signature"}, 400

FastAPI Example

from fastapi import FastAPI, Request, HTTPException
from elevenlabs import ElevenLabs, BadRequestError

app = FastAPI()
client = ElevenLabs(api_key="YOUR_API_KEY")

@app.post("/webhook")
async def handle_webhook(request: Request):
    # Get raw body and signature
    raw_body = await request.body()
    signature = request.headers.get("elevenlabs-signature")
    
    try:
        event = client.webhooks.construct_event(
            rawBody=raw_body.decode("utf-8"),
            sig_header=signature,
            secret="your_webhook_secret"
        )
        
        # Process the event
        await process_webhook_event(event)
        
        return {"success": True}
    except BadRequestError as e:
        raise HTTPException(status_code=400, detail=str(e.body.error))

Webhook Signature Verification

The SDK provides the construct_event method to verify webhook signatures and prevent unauthorized requests.

How It Works

ElevenLabs signs each webhook with a secret key and includes:

A timestamp (t=) to prevent replay attacks
A signature hash (v0=) to verify authenticity

from elevenlabs import ElevenLabs, BadRequestError

client = ElevenLabs(api_key="YOUR_API_KEY")

try:
    event = client.webhooks.construct_event(
        rawBody=request_body,  # Must be raw string, not parsed JSON
        sig_header="t=1234567890,v0=hash_value",
        secret="your_webhook_secret"
    )
    # Event is verified and safe to use
    print(event)
except BadRequestError as e:
    # Signature verification failed
    print(f"Error: {e.body.error}")

rawBody

str

required

The raw webhook request body as a string. Do not parse it as JSON first.

sig_header

str

required

The elevenlabs-signature header from the webhook request.

secret

str

required

Your webhook secret from the ElevenLabs dashboard.

Verification Errors

The construct_event method raises BadRequestError for the following issues:

Missing signature header

The elevenlabs-signature header was not included in the request.

# Error: "Missing signature header"

Webhook secret not configured

No secret was provided to the verification function.

# Error: "Webhook secret not configured"

Invalid signature format

The signature header doesn’t contain the expected t= and v0= components.

# Error: "No signature hash found with expected scheme v0"

Timestamp outside tolerance

The webhook timestamp is older than 30 minutes, indicating a potential replay attack.

# Error: "Timestamp outside the tolerance zone"

Signature mismatch

The computed signature doesn’t match the provided signature.

# Error: "Signature hash does not match the expected signature hash for payload"

Security Best Practices

Always verify signatures

Never process webhook events without verifying the signature first.

Use HTTPS

Only accept webhooks over HTTPS to prevent man-in-the-middle attacks.

Keep secrets secure

Store webhook secrets in environment variables, not in code.

Handle replay attacks

The 30-minute timestamp tolerance helps prevent replay attacks.

Processing Webhook Events

Once verified, process the webhook payload based on the event type:

def process_webhook_event(event: dict):
    event_type = event.get("type")
    
    if event_type == "audio.generated":
        handle_audio_generated(event)
    elif event_type == "voice.cloned":
        handle_voice_cloned(event)
    elif event_type == "usage.threshold":
        handle_usage_threshold(event)
    else:
        print(f"Unknown event type: {event_type}")

def handle_audio_generated(event):
    audio_id = event.get("data", {}).get("audio_id")
    print(f"Audio {audio_id} has been generated")
    # Your logic here

def handle_voice_cloned(event):
    voice_id = event.get("data", {}).get("voice_id")
    print(f"Voice {voice_id} has been cloned")
    # Your logic here

def handle_usage_threshold(event):
    threshold = event.get("data", {}).get("threshold")
    print(f"Usage threshold reached: {threshold}%")
    # Your logic here

Async Webhook Handling

The async client also supports webhook verification:

from elevenlabs import AsyncElevenLabs, BadRequestError
from fastapi import FastAPI, Request, HTTPException

app = FastAPI()
client = AsyncElevenLabs(api_key="YOUR_API_KEY")

@app.post("/webhook")
async def handle_webhook(request: Request):
    raw_body = await request.body()
    signature = request.headers.get("elevenlabs-signature")
    
    try:
        # Note: construct_event is synchronous even on async client
        event = client.webhooks.construct_event(
            rawBody=raw_body.decode("utf-8"),
            sig_header=signature,
            secret="your_webhook_secret"
        )
        
        # Process asynchronously
        await process_event_async(event)
        
        return {"success": True}
    except BadRequestError as e:
        raise HTTPException(status_code=400, detail=str(e.body.error))

async def process_event_async(event: dict):
    # Your async processing logic
    event_type = event.get("type")
    print(f"Processing event: {event_type}")

The construct_event method is synchronous even when using AsyncElevenLabs because it only performs local computation (HMAC verification). No API calls are made.

Complete Example

Here’s a complete webhook handler with proper error handling:

from flask import Flask, request, jsonify
from elevenlabs import ElevenLabs, BadRequestError
import os
import logging

app = Flask(__name__)
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

client = ElevenLabs(api_key=os.getenv("ELEVENLABS_API_KEY"))
WEBHOOK_SECRET = os.getenv("ELEVENLABS_WEBHOOK_SECRET")

@app.route("/webhook", methods=["POST"])
def handle_webhook():
    # Get raw body - important: don't parse as JSON first
    raw_body = request.get_data(as_text=True)
    signature = request.headers.get("elevenlabs-signature")
    
    # Verify webhook signature
    try:
        event = client.webhooks.construct_event(
            rawBody=raw_body,
            sig_header=signature,
            secret=WEBHOOK_SECRET
        )
    except BadRequestError as e:
        logger.error(f"Webhook signature verification failed: {e.body.error}")
        return jsonify({"error": "Invalid signature"}), 400
    except Exception as e:
        logger.error(f"Unexpected error during webhook verification: {e}")
        return jsonify({"error": "Internal server error"}), 500
    
    # Process the verified event
    try:
        event_type = event.get("type")
        logger.info(f"Processing webhook event: {event_type}")
        
        if event_type == "audio.generated":
            process_audio_generated(event)
        elif event_type == "voice.cloned":
            process_voice_cloned(event)
        else:
            logger.warning(f"Unhandled event type: {event_type}")
        
        return jsonify({"success": True}), 200
    except Exception as e:
        logger.error(f"Error processing webhook: {e}")
        # Return 200 anyway to prevent retries for processing errors
        return jsonify({"success": False, "error": str(e)}), 200

def process_audio_generated(event):
    data = event.get("data", {})
    audio_id = data.get("audio_id")
    logger.info(f"Audio generated: {audio_id}")
    # Your business logic here

def process_voice_cloned(event):
    data = event.get("data", {})
    voice_id = data.get("voice_id")
    logger.info(f"Voice cloned: {voice_id}")
    # Your business logic here

if __name__ == "__main__":
    app.run(port=5000)

Testing Webhooks

During development, use tools like ngrok to expose your local server:

# Install ngrok
brew install ngrok  # macOS
# or download from https://ngrok.com

# Start your webhook server
python webhook_server.py

# In another terminal, expose it
ngrok http 5000

# Use the ngrok URL in ElevenLabs dashboard
# Example: https://abc123.ngrok.io/webhook

Use ngrok or a similar tool to test webhooks locally without deploying to a server.

Webhook Response Guidelines

Return 200 for successful processing

Always return a 200 status code when the webhook is processed successfully, even if your business logic encounters non-critical errors.

Return 400 for invalid signatures

Return 400 when signature verification fails to indicate a client error.

Handle retries gracefully

ElevenLabs will retry failed webhooks. Make your endpoint idempotent to handle duplicate events.

Respond quickly

Process webhooks asynchronously if needed. Respond within 30 seconds to avoid timeouts.

Important: Always use the raw request body for signature verification. Parsing it as JSON first will cause verification to fail due to formatting differences.

Troubleshooting

Signature Verification Fails

Ensure you’re passing the raw request body, not parsed JSON
Check that your webhook secret matches the one in your dashboard
Verify the signature header is being read correctly
Check server time synchronization (timestamp tolerance is 30 minutes)

Missing Signature Header

if not request.headers.get("elevenlabs-signature"):
    logger.error("Missing elevenlabs-signature header")
    return {"error": "No signature"}, 400

Testing Signature Verification

# Test with a known good signature
def test_webhook_verification():
    client = ElevenLabs(api_key="test_key")
    
    test_body = '{"type":"test","data":{}}'
    test_secret = "test_secret"
    
    # Generate test signature
    import hmac
    import hashlib
    import time
    
    timestamp = str(int(time.time()))
    message = f"{timestamp}.{test_body}"
    signature = hmac.new(
        test_secret.encode(),
        message.encode(),
        hashlib.sha256
    ).hexdigest()
    
    sig_header = f"t={timestamp},v0={signature}"
    
    try:
        event = client.webhooks.construct_event(
            rawBody=test_body,
            sig_header=sig_header,
            secret=test_secret
        )
        print("Verification successful!", event)
    except BadRequestError as e:
        print(f"Verification failed: {e.body.error}")

Getting Started

Core Features

Conversational AI

Advanced Features

Guides

Overview

Setting Up Webhooks

Configure Your Endpoint

FastAPI Example

Webhook Signature Verification

How It Works

Verification Errors

Security Best Practices

Always verify signatures

Use HTTPS

Keep secrets secure

Handle replay attacks

Processing Webhook Events

Async Webhook Handling

Complete Example

Testing Webhooks

Webhook Response Guidelines

Troubleshooting

Signature Verification Fails

Missing Signature Header

Testing Signature Verification

Next Steps

Error Handling

Async Client

Build docs developers (and LLMs) love

Getting Started

Core Features

Conversational AI

Advanced Features

Guides

​Overview

​Setting Up Webhooks

​Configure Your Endpoint

​FastAPI Example

​Webhook Signature Verification

​How It Works

​Verification Errors

​Security Best Practices

Always verify signatures

Use HTTPS

Keep secrets secure

Handle replay attacks

​Processing Webhook Events

​Async Webhook Handling

​Complete Example

​Testing Webhooks

​Webhook Response Guidelines

​Troubleshooting

​Signature Verification Fails

​Missing Signature Header

​Testing Signature Verification

​Next Steps

Error Handling

Async Client

Build docs developers (and LLMs) love

Overview

Setting Up Webhooks

Configure Your Endpoint

FastAPI Example

Webhook Signature Verification

How It Works

Verification Errors

Security Best Practices

Processing Webhook Events

Async Webhook Handling

Complete Example

Testing Webhooks

Webhook Response Guidelines

Troubleshooting

Signature Verification Fails

Missing Signature Header

Testing Signature Verification

Next Steps