Skip to main content
Echo Mode lets you send text or audio input for the persona to speak. This mode is best suited when your application doesn’t require speech recognition or perception capabilities or if you already use a custom ASR/Perception pipeline.
Note: External ASR systems are typically slower and less optimized than Tavus’ built-in pipeline.

​
Prerequisites

Before you begin, ensure the following dependencies are installed:

​
Create an Echo Persona

1

Step 1: Get an API Key

  1. Go to the Developer Portal and select API Key from the sidebar menu.
  2. Click Create New Key to begin generating your API key.
  3. Enter a name for the key and (optional) specify allowed IP addresses, then click Create API Key.
  4. Copy your newly created API key and store it securely.
We cannot recover your API Key if you lose it.
2

Step 2: Create an Echo Persona

Use the following request to create a persona:
cURL
curl --request POST \
  --url https://tavusapi.com/v2/personas \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '{
    "persona_name": "Echo Assistant",
    "pipeline_mode": "echo"
  }'
3

Step 3: Create a Conversation

Create a conversation with your newly created persona_id:
cURL
curl --request POST \
  --url https://tavusapi.com/v2/conversations \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api_key>' \
  --data '{
    "persona_id": "<your_persona_id>",
    "conversation_name": "Echo Test"
  }'
4

Step 4: Create an App

Create a file named script.py and paste the following code:
import sys
from flask import Flask, jsonify, request
from daily import CallClient, Daily, EventHandler

app = Flask(__name__)

# Global client instance
call_client = None

class RoomHandler(EventHandler):
    def __init__(self):
        super().__init__()

    def on_app_message(self, message, sender: str) -> None:
        print(f"Incoming app message from {sender}: {message}")

def join_room(url):
    global call_client
    try:
        Daily.init()
        handler = RoomHandler()
        call_client = CallClient(event_handler=handler)
        call_client.join(url)
        print(f"Joined room: {url}")
    except Exception as e:
        print(f"Error joining room: {e}")
        raise

@app.route("/send_text_message", methods=["POST"])
def send_text_message():
    global call_client
    if not call_client:
        return jsonify({"error": "Not connected to a room"}), 400

    try:
        body = request.json
        conversation_id = body.get("conversation_id")
        properties = body.get("properties", {})
        message = {
            "message_type": "conversation",
            "event_type": "conversation.echo",
            "conversation_id": conversation_id,
            "properties": {
                "modality": properties.get("modality"),
                "text": properties.get("text"),
                "audio": properties.get("audio"),
                "sample_rate": properties.get("sample_rate", 16000),
                "inference_id": properties.get("inference_id"),
                "done": properties.get("done")
            }
        }
        call_client.send_app_message(message)
        return jsonify({"status": "Message sent successfully"}), 200
    except Exception as e:
        return jsonify({"error": f"Failed to send message: {str(e)}"}), 500

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: python script.py <conversation_url>")
        sys.exit(1)

    conversation_url = sys.argv[1]
    try:
        join_room(conversation_url)
        app.run(port=8000, debug=True)
    except Exception as e:
        print(f"Failed to start the application: {e}")
        sys.exit(1)
This script starts a Flask app that connects to a Daily room and sends echo interaction messages to your persona.
5

Step 5: Execute the Code

Run the script:
python script.py <conversation_url>
Replace <conversation_url> with the URL returned when creating your conversation.
6

Step 6: Send Echo Message

Send a POST request to your local server to trigger an echo message:
cURL
curl -X POST http://localhost:8000/send_text_message \
  -H "Content-Type: application/json" \
  -d '{
    "message_type": "conversation",
    "event_type": "conversation.echo",
    "conversation_id": "<conversation-id>",
    "properties": {
      "modality": "text",
      "text": "Hello there!",
      "audio": "base64-encoded-audio",
      "sample_rate": 24000,
      "inference_id": "inference-id-123",
      "done": "true"
    }
  }'
In this example, the persona will respond by saying: “Hello there!”