Implementing the Genesys Cloud Guest API for Headless Messaging

How-To-Articles
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Implementing the Genesys Cloud Guest API for Headless Messaging

What You Will Build

You will build a backend service that sends and receives messages to and from Genesys Cloud without using the standard Web Messenger widget or client-side JavaScript SDK.
This tutorial uses the Genesys Cloud Platform API (specifically the Messaging and Conversations APIs) to simulate a guest user via server-side logic.
The implementation covers Python 3.10+ using the purecloud-platform-client-v2 SDK and the requests library for lower-level HTTP interactions where the SDK lacks specific guest endpoints.

Prerequisites

  • OAuth Client: A Genesys Cloud OAuth client with the public access type is recommended for external integrations, though confidential works for internal services.
  • Required Scopes:
    • conversations:read
    • messaging:read
    • messaging:write
    • users:read (to identify agents if needed)
    • routing:read (if using routing APIs to select queues)
  • SDK Version: purecloud-platform-client-v2 version 130.0.0 or higher.
  • Runtime: Python 3.10+
  • Dependencies:
    pip install purecloud-platform-client-v2 requests python-dotenv
  • Genesys Cloud Environment: An active Genesys Cloud organization with Web Messaging enabled and at least one Queue configured for Web Messaging.

Authentication Setup

The Guest API does not use standard user authentication. Instead, it relies on a Conversation ID and a Participant ID (the Guest) that are established when the conversation is initiated. However, to create that conversation via the API, your backend service must authenticate using your OAuth Client credentials.

We will use the Authorization Code Grant or Client Credentials Grant depending on your setup. For a backend service that acts on behalf of a system, Client Credentials is standard. If you are acting on behalf of a known user (e.g., an employee using an internal tool), use Authorization Code.

Here is the setup for the SDK client using Client Credentials:

import os
from purecloud.platform.client.configuration import Configuration
from purecloud.platform.client.rest import ApiException
from purecloud.platform.client import ApiClient
from dotenv import load_dotenv

# Load environment variables
load_dotenv()

def get_platform_client() -> ApiClient:
    """
    Initializes and returns an authenticated Genesys Cloud API client.
    """
    configuration = Configuration()
    
    # Set the host (e.g., 'api.mypurecloud.com' or 'api.us.genesyscloud.com')
    configuration.host = os.getenv("GENESYS_HOST", "api.mypurecloud.com")
    
    # OAuth Client Credentials
    client_id = os.getenv("GENESYS_CLIENT_ID")
    client_secret = os.getenv("GENESYS_CLIENT_SECRET")
    
    if not client_id or not client_secret:
        raise ValueError("GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET must be set in environment.")

    # Initialize the API client with client credentials flow
    client = ApiClient(configuration)
    client.client_credentials_authorization(client_id, client_secret)
    
    return client

# Initialize the client once
api_client = get_platform_client()

Critical Note: The OAuth token obtained here is for your service, not the guest. The guest is identified by a user_id (usually a UUID) that you generate or manage in your own database. This user_id is passed to the Genesys APIs as the external_user_id or within the conversation payload.

Implementation

Step 1: Initiating a Conversation

To send a message as a guest, you must first create a conversation. In the standard web flow, this happens when the user clicks “Start Chat”. In the API flow, you create the conversation resource directly.

We will use the POST /api/v2/conversations/messaging endpoint. This endpoint creates a messaging conversation and returns a conversationId.

Required OAuth Scope: messaging:write, conversations:write

from purecloud.platform.conversations.api import ConversationsApi
from purecloud.platform.conversations.model import MessagingConversationCreateRequest
from purecloud.platform.conversations.model import MessagingConversationParticipant

def initiate_guest_conversation(queue_id: str, guest_external_id: str, initial_message: str) -> str:
    """
    Creates a new messaging conversation and returns the conversation ID.
    
    Args:
        queue_id: The ID of the Genesys Cloud Queue to route to.
        guest_external_id: Your internal ID for the guest (e.g., 'user-123' or a UUID).
        initial_message: The first message the guest sends.
        
    Returns:
        str: The Genesys Cloud conversation ID.
    """
    api = ConversationsApi(api_client)
    
    # 1. Define the Guest Participant
    # We use 'external_user_id' to link this Genesys participant to your internal user record.
    guest_participant = MessagingConversationParticipant(
        external_user_id=guest_external_id,
        name="Guest User", # Optional: Display name for the guest
        email="guest@example.com" # Optional: Email for transcripts
    )
    
    # 2. Construct the Create Request
    # Note: The 'queue' field is crucial for routing.
    create_request = MessagingConversationCreateRequest(
        queue_id=queue_id,
        participants=[guest_participant],
        initial_message=initial_message # This sends the first message immediately
    )
    
    try:
        # 3. Execute the API call
        response = api.post_conversations_messaging(body=create_request)
        
        print(f"Conversation created: {response.id}")
        return response.id
        
    except ApiException as e:
        print(f"Exception when calling ConversationsApi->post_conversations_messaging: {e}\n")
        raise

Expected Response Body (JSON):

{
  "id": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
  "type": "message",
  "state": "active",
  "participants": [
    {
      "id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
      "external_user_id": "user-123",
      "name": "Guest User",
      "role": "customer",
      "state": "connected"
    }
  ],
  "queue": {
    "id": "98765432-1234-5678-9abc-def012345678",
    "name": "Support Queue"
  },
  "created_time": "2023-10-27T10:00:00.000Z",
  "updated_time": "2023-10-27T10:00:00.000Z"
}

Step 2: Sending Subsequent Messages

Once the conversation exists, you do not need to re-authenticate as the guest. You simply send messages to the conversation using the conversationId. The API determines which participant is sending the message based on the participant_id included in the payload.

You must retrieve the participant_id from the response in Step 1. If you only have the external_user_id, you can query the conversation to find the participant ID, but caching it is more efficient.

Required OAuth Scope: messaging:write

from purecloud.platform.conversations.model import MessageCreateRequest

def send_guest_message(conversation_id: str, participant_id: str, message_text: str) -> bool:
    """
    Sends a message from the guest to the conversation.
    
    Args:
        conversation_id: The Genesys Cloud conversation ID.
        participant_id: The participant ID of the guest (not the external_user_id).
        message_text: The content of the message.
        
    Returns:
        bool: True if successful.
    """
    api = ConversationsApi(api_client)
    
    # Construct the message payload
    # The 'participant_id' field is mandatory to identify who is sending the message.
    message_request = MessageCreateRequest(
        participant_id=participant_id,
        text=message_text
    )
    
    try:
        # Send the message
        api.post_conversations_messaging_messages(
            conversation_id=conversation_id,
            body=message_request
        )
        return True
        
    except ApiException as e:
        if e.status == 429:
            print("Rate limited. Implement retry logic with exponential backoff.")
        elif e.status == 404:
            print(f"Conversation {conversation_id} not found.")
        else:
            print(f"Error sending message: {e}")
        raise

Step 3: Receiving Messages (Polling vs. Webhooks)

There are two ways to receive messages from agents or system updates. For a “headless” implementation, Webhooks are the production standard. However, for debugging or simple scripts, Polling the API is easier to implement.

Option A: Polling for New Messages

You can fetch the latest messages for a conversation. To avoid fetching history every time, track the updated_time or the last message ID.

Required OAuth Scope: conversations:read

def get_latest_messages(conversation_id: str, limit: int = 10) -> list:
    """
    Retrieves the most recent messages from a conversation.
    """
    api = ConversationsApi(api_client)
    
    try:
        # Get conversation details including messages
        # The 'expansion' parameter is critical to include messages in the response
        response = api.get_conversations_messaging_conversation(
            conversation_id=conversation_id,
            expand=['messages']
        )
        
        if response.messages:
            # Messages are typically returned in chronological order
            # Reverse to get newest first
            latest_msgs = response.messages[-limit:]
            return latest_msgs
        return []
        
    except ApiException as e:
        print(f"Error fetching messages: {e}")
        raise

Option B: Webhooks (Production Recommended)

In a real application, you should not poll. Instead, register a Webhook to receive events.

  1. Register Webhook: Use the POST /api/v2/webhooks endpoint.
  2. Event Type: conversation:updated or conversation:created.
  3. Filter: Filter by conversation.type = message and optionally by conversation.id if you want specific conversations.

Webhook Payload Structure:
When an agent replies, Genesys sends a JSON payload to your webhook URL. You must verify the signature (using your OAuth client secret) to ensure the request is legitimate.

{
  "webhookId": "webhook-123",
  "webhookName": "Guest Messaging Listener",
  "eventType": "conversation:updated",
  "data": {
    "id": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
    "type": "message",
    "state": "active",
    "participants": [
      {
        "id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
        "role": "customer",
        "external_user_id": "user-123",
        "state": "connected"
      },
      {
        "id": "agent-participant-id-xyz",
        "role": "agent",
        "user": {
          "id": "agent-user-id-123",
          "name": "John Agent"
        }
      }
    ],
    "messages": [
      {
        "id": "msg-id-123",
        "participant_id": "agent-participant-id-xyz",
        "text": "Hello! How can I help you today?",
        "created_time": "2023-10-27T10:05:00.000Z"
      }
    ]
  }
}

Handling the Webhook in Python (Flask Example):

from flask import Flask, request, jsonify
import hmac
import hashlib
import base64

app = Flask(__name__)

def verify_webhook_signature(payload: str, signature: str, secret: str) -> bool:
    """
    Verifies the Genesys Cloud webhook signature.
    """
    # The signature is a base64-encoded HMAC-SHA256 hash of the payload using the client secret
    expected_signature = hmac.new(
        secret.encode('utf-8'),
        payload.encode('utf-8'),
        hashlib.sha256
    ).digest()
    expected_signature_b64 = base64.b64encode(expected_signature).decode('utf-8')
    
    return hmac.compare_digest(expected_signature_b64, signature)

@app.route('/webhook/messaging', methods=['POST'])
def handle_messaging_webhook():
    payload = request.get_data(as_text=True)
    signature = request.headers.get('X-Genesys-Signature')
    
    # Replace with your actual client secret
    client_secret = os.getenv("GENESYS_CLIENT_SECRET")
    
    if not verify_webhook_signature(payload, signature, client_secret):
        return jsonify({"error": "Invalid signature"}), 401
    
    data = request.json
    
    # Process the event
    event_type = data.get('eventType')
    conversation_data = data.get('data', {})
    
    if event_type == 'conversation:updated':
        messages = conversation_data.get('messages', [])
        for msg in messages:
            participant_id = msg.get('participant_id')
            text = msg.get('text')
            
            # Identify if this is an agent message or guest message
            # You can compare participant_id against known guest participant IDs
            if participant_id != "known-guest-participant-id":
                print(f"Received Agent Message: {text}")
                # Trigger your internal logic here (e.g., notify user, update DB)
    
    return jsonify({"status": "success"}), 200

Complete Working Example

This script combines initialization, conversation creation, and a simple polling loop to demonstrate the full lifecycle.

import os
import time
from purecloud.platform.client.configuration import Configuration
from purecloud.platform.client.rest import ApiException
from purecloud.platform.client import ApiClient
from purecloud.platform.conversations.api import ConversationsApi
from purecloud.platform.conversations.model import MessagingConversationCreateRequest
from purecloud.platform.conversations.model import MessagingConversationParticipant
from purecloud.platform.conversations.model import MessageCreateRequest
from dotenv import load_dotenv

load_dotenv()

class GenesysGuestMessenger:
    def __init__(self):
        self.configuration = Configuration()
        self.configuration.host = os.getenv("GENESYS_HOST", "api.mypurecloud.com")
        self.api_client = ApiClient(self.configuration)
        self.api_client.client_credentials_authorization(
            os.getenv("GENESYS_CLIENT_ID"),
            os.getenv("GENESYS_CLIENT_SECRET")
        )
        self.conversations_api = ConversationsApi(self.api_client)

    def start_conversation(self, queue_id: str, guest_external_id: str, initial_text: str) -> dict:
        """Creates a conversation and returns metadata."""
        participant = MessagingConversationParticipant(
            external_user_id=guest_external_id,
            name="API Guest",
            email="guest@api.com"
        )
        
        create_req = MessagingConversationCreateRequest(
            queue_id=queue_id,
            participants=[participant],
            initial_message=initial_text
        )
        
        try:
            resp = self.conversations_api.post_conversations_messaging(body=create_req)
            # Extract the guest participant ID for future messages
            guest_participant_id = None
            for p in resp.participants:
                if p.external_user_id == guest_external_id:
                    guest_participant_id = p.id
                    break
            
            return {
                "conversation_id": resp.id,
                "participant_id": guest_participant_id,
                "state": resp.state
            }
        except ApiException as e:
            print(f"Failed to create conversation: {e}")
            raise

    def send_message(self, conversation_id: str, participant_id: str, text: str):
        """Sends a message to an existing conversation."""
        msg_req = MessageCreateRequest(
            participant_id=participant_id,
            text=text
        )
        try:
            self.conversations_api.post_conversations_messaging_messages(
                conversation_id=conversation_id,
                body=msg_req
            )
            print(f"Message sent: {text}")
        except ApiException as e:
            print(f"Failed to send message: {e}")

    def poll_for_messages(self, conversation_id: str, last_msg_id: str = None, timeout: int = 30) -> list:
        """
        Polls for new messages. In production, use webhooks.
        """
        start_time = time.time()
        while time.time() - start_time < timeout:
            try:
                resp = self.conversations_api.get_conversations_messaging_conversation(
                    conversation_id=conversation_id,
                    expand=['messages']
                )
                
                if resp.messages:
                    # Filter out messages we have already seen
                    new_messages = [m for m in resp.messages if m.id != last_msg_id]
                    if new_messages:
                        return new_messages
                
                time.sleep(2) # Wait before polling again
            except ApiException as e:
                print(f"Polling error: {e}")
                time.sleep(5)
        return []

# Usage Example
if __name__ == "__main__":
    # Configuration
    QUEUE_ID = os.getenv("GENESYS_QUEUE_ID")
    GUEST_ID = "unique-guest-123"
    
    if not QUEUE_ID:
        raise ValueError("Set GENESYS_QUEUE_ID in environment")

    messenger = GenesysGuestMessenger()
    
    # 1. Start Conversation
    print("Starting conversation...")
    conv_data = messenger.start_conversation(
        queue_id=QUEUE_ID,
        guest_external_id=GUEST_ID,
        initial_text="Hello, I need help with my order."
    )
    
    conv_id = conv_data['conversation_id']
    guest_participant_id = conv_data['participant_id']
    
    print(f"Conversation ID: {conv_id}")
    print(f"Guest Participant ID: {guest_participant_id}")
    
    # 2. Send Follow-up Message
    time.sleep(5) # Allow system to process
    messenger.send_message(
        conversation_id=conv_id,
        participant_id=guest_participant_id,
        text="Actually, I also have a question about shipping."
    )
    
    # 3. Poll for Agent Response
    print("Waiting for agent response...")
    last_msg_id = None # In a real app, track this
    responses = messenger.poll_for_messages(conv_id, last_msg_id, timeout=60)
    
    for msg in responses:
        if msg.participant_id != guest_participant_id:
            print(f"Agent replied: {msg.text}")

Common Errors & Debugging

Error: 401 Unauthorized

Cause: The OAuth token is expired, invalid, or the client credentials are incorrect.
Fix: Ensure GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET are correct. The SDK handles token refresh automatically, but if the client was recently revoked, re-initialize the ApiClient.

Error: 403 Forbidden

Cause: The OAuth client lacks the required scopes.
Fix: Check the OAuth client settings in Genesys Cloud Admin. Ensure messaging:write and conversations:read are added. If using a public client, ensure it is not restricted to specific users.

Error: 404 Not Found (Conversation)

Cause: The conversation_id is invalid or the conversation has been archived/deleted.
Fix: Verify the conversation_id returned from the creation step. Ensure you are using the correct Genesys Cloud environment (e.g., not sending a US ID to a EU API endpoint).

Error: 429 Too Many Requests

Cause: Rate limiting. Genesys Cloud enforces strict rate limits on API calls.
Fix: Implement exponential backoff. Do not poll every second. Use Webhooks instead of polling for real-time updates.

Error: Message Not Appearing in Agent Desktop

Cause: The participant_id used to send the message does not match the participant registered in the conversation.
Fix: Ensure you use the participant_id returned from the POST /api/v2/conversations/messaging response, not the external_user_id. The external_user_id is a metadata field; the participant_id is the system identifier for the messaging session.

Official References