Implementing Resilient WebSocket Reconnection for Genesys Cloud Notifications in Node.js

What You Will Build

• A production-grade WebSocket client that subscribes to Genesys Cloud real-time notifications and automatically recovers from connection drops.
• This implementation uses the Genesys Cloud REST API for authentication and the native WebSocket protocol for the notification stream.
• The code is written in TypeScript/Node.js using the ws library and the official Genesys Cloud SDK for token management.

Prerequisites

• OAuth Client Type: Public or Confidential Client with offline_access scope for refresh tokens.
• Required Scopes: notifications:subscribe, plus any specific resource scopes you intend to listen to (e.g., conversation:read, user:read).
• SDK Version: @genesyscloud/purecloud-platform-client-v2 (latest stable).
• Runtime: Node.js 18+ (for stable WebSocket support and modern async/await patterns).
• Dependencies:
  • @genesyscloud/purecloud-platform-client-v2
  • ws (WebSocket client library)
  • dotenv (for environment variable management)

Install dependencies:

npm install @genesyscloud/purecloud-platform-client-v2 ws dotenv
npm install --save-dev typescript @types/ws @types/node

Authentication Setup

Genesys Cloud WebSockets do not authenticate via the WebSocket handshake headers directly. Instead, you must obtain a valid JWT (JSON Web Token) using the REST API and pass it as the first message in the WebSocket stream.

We use the Genesys Cloud SDK to handle the OAuth2 Client Credentials flow. This abstracts away the complexity of token endpoint discovery and refresh logic.

import { Configuration, PlatformClient } from '@genesyscloud/purecloud-platform-client-v2';
import * as dotenv from 'dotenv';

dotenv.config();

const clientSecret = process.env.GENESYS_CLIENT_SECRET;
const clientId = process.env.GENESYS_CLIENT_ID;
const environment = process.env.GENESYS_ENVIRONMENT || 'mypurecloud.com';

if (!clientSecret || !clientId) {
    throw new Error('GENESYS_CLIENT_SECRET and GENESYS_CLIENT_ID are required');
}

const configuration = new Configuration({
    basePath: `https://${environment}`,
    clientId: clientId,
    clientSecret: clientSecret,
    grantType: 'client_credentials',
    // Define scopes required for both REST calls and WebSocket subscriptions
    scopes: [
        'notifications:subscribe',
        'conversation:read',
        'user:read'
    ]
});

const platformClient = new PlatformClient(configuration);

/**
 * Retrieves a fresh access token from the Genesys Cloud SDK.
 * The SDK handles caching and refreshing automatically.
 */
export async function getAccessToken(): Promise<string> {
    const authClient = platformClient.AuthClient;
    const tokenResponse = await authClient.getAccessToken();
    
    if (!tokenResponse.access_token) {
        throw new Error('Failed to retrieve access token');
    }
    
    return tokenResponse.access_token;
}

Implementation

Step 1: Establishing the WebSocket Connection

The Genesys Cloud Notification API uses a specific WebSocket endpoint: wss://api.mypurecloud.com/api/v2/notifications. Note that the host must match your environment (e.g., api.mypurecloud.com, api.usw2.pure.cloud).

The connection lifecycle is:

1. Open WebSocket connection.
2. Send a JSON payload containing the access_token.
3. Wait for the server to acknowledge authentication.
4. Send subscription messages.

import WebSocket from 'ws';

const GENESYS_WS_URL = `wss://api.${process.env.GENESYS_ENVIRONMENT || 'mypurecloud.com'}/api/v2/notifications`;

interface NotificationMessage {
    event: string;
    data: any;
}

export class GenesysNotificationClient {
    private ws: WebSocket | null = null;
    private isReconnecting = false;
    private reconnectAttempts = 0;
    private maxReconnectAttempts = 10;
    private reconnectDelayMs = 1000;
    private subscriptions: string[] = [];

    constructor(private getAccessTokenFn: () => Promise<string>) {}

    /**
     * Initiates the WebSocket connection.
     */
    async connect(): Promise<void> {
        if (this.ws && this.ws.readyState === WebSocket.OPEN) {
            return;
        }

        console.log('Connecting to Genesys Cloud Notifications...');
        
        this.ws = new WebSocket(GENESYS_WS_URL);

        this.ws.on('open', () => {
            console.log('WebSocket connection established.');
            this.handleConnectionOpen();
        });

        this.ws.on('message', (data) => {
            this.handleMessage(data.toString());
        });

        this.ws.on('error', (error) => {
            console.error('WebSocket error:', error.message);
            this.handleReconnect();
        });

        this.ws.on('close', (code, reason) => {
            console.log(`WebSocket closed with code ${code}: ${reason.toString()}`);
            this.handleReconnect();
        });
    }

    private handleConnectionOpen() {
        // Step 1: Authenticate immediately after opening
        this.authenticate();
    }

    private async authenticate() {
        if (!this.ws || this.ws.readyState !== WebSocket.OPEN) return;

        try {
            const token = await this.getAccessTokenFn();
            
            // Send authentication payload
            const authPayload = {
                access_token: token
            };

            this.ws.send(JSON.stringify(authPayload));
            console.log('Authentication message sent.');

        } catch (error) {
            console.error('Failed to authenticate:', error);
            this.ws?.close();
        }
    }

    private handleMessage(data: string) {
        try {
            const message = JSON.parse(data) as NotificationMessage;
            
            // Genesys Cloud sends a 'connected' event after successful auth
            if (message.event === 'connected') {
                console.log('Authenticated successfully.');
                this.reconnectAttempts = 0; // Reset attempts on success
                this.isReconnecting = false;
                
                // Re-subscribe to topics if we had any
                if (this.subscriptions.length > 0) {
                    this.subscriptions.forEach(topic => this.subscribe(topic));
                }
                return;
            }

            // Handle actual notifications
            if (message.event && message.data) {
                console.log(`Received event: ${message.event}`);
                // Process your business logic here
                this.processNotification(message);
            }
        } catch (error) {
            console.error('Failed to parse message:', error);
        }
    }

    private processNotification(message: NotificationMessage) {
        // Placeholder for business logic
        console.log(`Processing ${message.event}:`, JSON.stringify(message.data).substring(0, 100));
    }

    private handleReconnect() {
        if (this.isReconnecting) return;

        if (this.reconnectAttempts >= this.maxReconnectAttempts) {
            console.error('Max reconnection attempts reached. Giving up.');
            return;
        }

        this.isReconnecting = true;
        this.reconnectAttempts++;
        
        // Exponential backoff: 1s, 2s, 4s, 8s... capped at 30s
        const delay = Math.min(this.reconnectDelayMs * Math.pow(2, this.reconnectAttempts - 1), 30000);
        
        console.log(`Reconnecting in ${delay}ms (attempt ${this.reconnectAttempts})...`);

        setTimeout(() => {
            this.connect();
        }, delay);
    }

    /**
     * Subscribes to a specific notification topic.
     * Topics follow the format: /{resource}/{id}
     * Example: /conversations/conversations/{conversationId}
     */
    subscribe(topic: string) {
        this.subscriptions.push(topic);
        
        if (this.ws && this.ws.readyState === WebSocket.OPEN) {
            const subscribePayload = {
                topic: topic
            };
            this.ws.send(JSON.stringify(subscribePayload));
            console.log(`Subscribed to: ${topic}`);
        }
    }

    disconnect() {
        if (this.ws) {
            this.ws.close();
            this.ws = null;
        }
    }
}

Step 2: Handling Subscription Lifecycle

A common mistake is assuming subscriptions persist across reconnections. They do not. When the WebSocket drops, the server forgets your subscriptions. The client must re-send all subscribe messages after the connected event is received.

In the code above, handleConnectionOpen triggers authentication. Once the server responds with event: 'connected', the handleMessage method iterates through this.subscriptions and re-sends them. This ensures state consistency.

You must also handle the case where the connection is still OPEN but the server sends a close frame. The ws library emits the close event, which triggers handleReconnect.

Step 3: Managing Token Expiration During Long Connections

Access tokens expire (typically every 20-30 minutes). If your WebSocket connection stays open longer than the token lifetime, the server may stop sending messages or close the connection.

The Genesys Cloud SDK (PlatformClient) automatically refreshes tokens when you call getAccessToken(). However, the WebSocket itself does not know the token has changed. You have two options:

1. Proactive Refresh: Periodically re-send the authentication message with the new token.
2. Reactive Refresh: Allow the connection to drop or fail, then reconnect with a fresh token.

The implementation above uses the Reactive approach for simplicity and robustness. If the token expires, the server may send an error or close the connection. The close handler triggers handleReconnect, which calls getAccessTokenFn again. The SDK returns a fresh token, and the cycle repeats.

If you prefer proactive refresh, you can add a timer:

private startTokenRefreshTimer(intervalMs: number = 15 * 60 * 1000) {
    setInterval(async () => {
        if (this.ws && this.ws.readyState === WebSocket.OPEN) {
            try {
                const token = await this.getAccessTokenFn();
                this.ws.send(JSON.stringify({ access_token: token }));
                console.log('Token refreshed proactively.');
            } catch (error) {
                console.error('Token refresh failed:', error);
            }
        }
    }, intervalMs);
}

Complete Working Example

This script demonstrates how to initialize the client, subscribe to a specific user’s presence updates, and handle the stream.

import { GenesysNotificationClient } from './notification-client'; // Assuming the class above is in this file
import { getAccessToken } from './auth'; // Assuming the auth function above is in this file

async function main() {
    // 1. Initialize the client
    const client = new GenesysNotificationClient(getAccessToken);

    // 2. Define the topic you want to listen to
    // Replace 'USER_ID' with a real user ID from your Genesys Cloud instance
    const userId = process.env.GENESYS_USER_ID || 'YOUR_USER_ID_HERE';
    const presenceTopic = `/users/${userId}/presence`;

    // 3. Connect and Subscribe
    try {
        await client.connect();
        
        // Wait a moment for connection to stabilize (in production, use a promise-based ready state check)
        setTimeout(() => {
            client.subscribe(presenceTopic);
        }, 2000);

        console.log(`Listening to presence updates for user: ${userId}`);
        console.log('Press Ctrl+C to exit.');

    } catch (error) {
        console.error('Initialization failed:', error);
        process.exit(1);
    }

    // Handle graceful shutdown
    process.on('SIGINT', () => {
        console.log('\nShutting down...');
        client.disconnect();
        process.exit(0);
    });
}

main();

Common Errors & Debugging

Error: 401 Unauthorized on WebSocket Message

Cause: The access token sent in the initial message is invalid, expired, or lacks the notifications:subscribe scope.

Fix:

1. Verify your OAuth Client has the notifications:subscribe scope.
2. Check that the token returned by getAccessToken() is not expired.
3. Ensure you are sending the token as a JSON object { "access_token": "..." }, not as a plain string.

Debug Code:

// In handleConnectionOpen
const token = await this.getAccessTokenFn();
console.log('Token preview:', token.substring(0, 20) + '...'); // Log first 20 chars
this.ws.send(JSON.stringify({ access_token: token }));

Error: 403 Forbidden on Subscription

Cause: The token used for authentication lacks the specific scope required for the resource you are subscribing to. For example, subscribing to /conversations/conversations/{id} requires conversation:read.

Fix:
Add the necessary resource scopes to your OAuth client configuration and regenerate the token.

// In Configuration
scopes: [
    'notifications:subscribe',
    'conversation:read', // Required for conversation notifications
    'user:read'          // Required for user notifications
]

Error: Connection Drops Randomly

Cause: Network instability, firewall timeouts, or Genesys Cloud server-side cleanup of idle connections.

Fix:
The exponential backoff logic in handleReconnect is designed for this. Ensure your maxReconnectAttempts is high enough for transient failures. If you are behind a proxy or firewall, ensure that WebSocket connections (ws:// or wss://) are allowed and not terminated by intermediate devices.

Error: WebSocket is not open

Cause: Attempting to send a message (subscribe or auth) before the open event fires.

Fix:
Always check this.ws.readyState === WebSocket.OPEN before calling this.ws.send(). The provided implementation includes this check in the subscribe method.

Official References

• Genesys Cloud Notification API Documentation
• Genesys Cloud WebSocket Protocol Details
• Genesys Cloud OAuth2 Scopes Reference
• Node.js ws Library Documentation