Extending Genesys Cloud Web Messaging Client SDK with TypeScript

What You Will Build

A production-grade React component that intercepts the Genesys Cloud Web Messaging client message stream, parses markdown payloads into rich text, renders interactive carousel attachments, handles media playback failures with automatic thumbnail fallback, and synchronizes read receipts with the server via WebSocket acknowledgment messages. This tutorial uses the @genesys/web-messaging-client SDK and @genesys/web-messaging-ui types with TypeScript and React 18.

Prerequisites

• OAuth 2.0 Client Credentials grant type with webmessaging:send and webmessaging:read scopes
• Genesys Cloud Web Messaging deployment ID and region identifier
• Node.js 18.0 or higher
• React 18.0 or higher with TypeScript 5.0 or higher
• External dependencies: @genesys/web-messaging-client@^2.0.0, react-markdown@^9.0.0, remark-gfm@^4.0.0, axios@^1.6.0

Authentication Setup

The Web Messaging client SDK requires a JSON Web Token to establish the WebSocket connection. You must generate this token via the Genesys Cloud REST API before initializing the client. The endpoint supports standard OAuth 2.0 client credentials authentication and returns a signed JWT that the WebSocket layer validates.

The following TypeScript utility fetches the JWT with built-in retry logic for 429 rate limit responses and exponential backoff.

import axios, { AxiosError } from 'axios';

export interface WebMessagingJwtPayload {
  jwt: string;
  expiresAt: string;
}

export async function fetchWebMessagingJwt(
  clientId: string,
  clientSecret: string,
  deploymentId: string,
  region: string
): Promise<string> {
  const baseUrl = `https://${region}.mypurecloud.com`;
  
  // Step 1: Obtain OAuth access token
  const tokenResponse = await axios.post(
    `${baseUrl}/oauth/token`,
    new URLSearchParams({ grant_type: 'client_credentials', scope: 'webmessaging:send webmessaging:read' }),
    {
      auth: { username: clientId, password: clientSecret },
      headers: { 'Content-Type': 'application/x-www-form-urlencoded' }
    }
  );
  
  const accessToken = tokenResponse.data.access_token;
  
  // Step 2: Request Web Messaging JWT with retry logic for 429
  const jwtUrl = `${baseUrl}/api/v2/webdeployments/messages/jwt`;
  let jwtPayload: WebMessagingJwtPayload | null = null;
  const maxRetries = 3;
  let delay = 1000;

  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    try {
      const response = await axios.post<WebMessagingJwtPayload>(
        jwtUrl,
        { deploymentId },
        { headers: { Authorization: `Bearer ${accessToken}` } }
      );
      jwtPayload = response.data;
      break;
    } catch (error) {
      const axiosError = error as AxiosError;
      if (axiosError.response?.status === 429 && attempt < maxRetries) {
        console.warn(`Rate limited on JWT request. Retrying in ${delay}ms...`);
        await new Promise(resolve => setTimeout(resolve, delay));
        delay *= 2;
      } else {
        throw axiosError;
      }
    }
  }

  if (!jwtPayload) {
    throw new Error('Failed to obtain Web Messaging JWT after maximum retries');
  }

  return jwtPayload.jwt;
}

The JWT generation endpoint requires the webmessaging:send scope. The retry logic prevents cascading failures when the Genesys Cloud API enforces rate limits. You must cache the returned JWT and refresh it before the expiresAt timestamp triggers a WebSocket disconnect.

Implementation

Step 1: Initialize the WebSocket Client and Intercept Message Streams

The Genesys Cloud Web Messaging client SDK exposes an event-driven interface. You instantiate the WebMessagingClient with your deployment credentials and subscribe to the message event. Intercepting this stream allows you to bypass the default UI renderer and push messages into a custom React state manager.

import { WebMessagingClient, Message, ClientEvent } from '@genesys/web-messaging-client';
import { useCallback, useEffect, useState } from 'react';

interface MessagingClientConfig {
  deploymentId: string;
  region: string;
  jwt: string;
  userId?: string;
  userIdentity?: string;
}

export function useWebMessagingClient(config: MessagingClientConfig) {
  const [client, setClient] = useState<WebMessagingClient | null>(null);
  const [isConnected, setIsConnected] = useState(false);
  const [messages, setMessages] = useState<Message[]>([]);

  useEffect(() => {
    const wsClient = new WebMessagingClient({
      deploymentId: config.deploymentId,
      region: config.region,
      jwt: config.jwt,
      userId: config.userId,
      userIdentity: config.userIdentity,
    });

    wsClient.on(ClientEvent.CONNECTED, () => {
      console.log('WebSocket connection established');
      setIsConnected(true);
    });

    wsClient.on(ClientEvent.DISCONNECTED, (error) => {
      console.error('WebSocket disconnected:', error);
      setIsConnected(false);
    });

    // Intercept message rendering stream
    wsClient.on(ClientEvent.MESSAGE, (message: Message) => {
      setMessages(prev => [...prev, message]);
    });

    wsClient.connect();
    setClient(wsClient);

    return () => {
      wsClient.disconnect();
    };
  }, [config.deploymentId, config.region, config.jwt, config.userId, config.userIdentity]);

  const acknowledgeMessage = useCallback((messageId: string) => {
    if (client) {
      client.acknowledgeMessage(messageId).catch(err => {
        console.error('Failed to acknowledge message:', err);
      });
    }
  }, [client]);

  return { client, isConnected, messages, acknowledgeMessage };
}

The ClientEvent.MESSAGE listener captures every inbound and outbound message. Storing messages in React state enables controlled rendering. The acknowledgeMessage method sends a WebSocket frame to the Genesys Cloud server, marking the conversation position as read. You must call this method explicitly because the SDK does not auto-acknowledge messages for custom UI implementations.

Step 2: Build the Custom Message Renderer with Markdown and Carousel Support

Genesys Cloud messages can contain plain text, markdown, or structured attachments. The SDK normalizes these into a content field and an attachments array. You must parse markdown safely and render carousel attachments as interactive React components. The following renderer uses react-markdown with GFM support and maps carousel payloads to a swipeable card interface.

import React, { useState } from 'react';
import ReactMarkdown from 'react-markdown';
import remarkGfm from 'remark-gfm';
import { Message, AttachmentType } from '@genesys/web-messaging-client';

interface CarouselItem {
  title: string;
  description: string;
  imageUrl?: string;
  actionUrl?: string;
}

interface CarouselAttachment {
  type: 'carousel';
  items: CarouselItem[];
}

const MarkdownRenderer: React.FC<{ content: string }> = ({ content }) => (
  <div className="markdown-content">
    <ReactMarkdown remarkPlugins={[remarkGfm]}>
      {content}
    </ReactMarkdown>
  </div>
);

const CarouselRenderer: React.FC<{ attachment: CarouselAttachment }> = ({ attachment }) => {
  const [activeIndex, setActiveIndex] = useState(0);

  const handleNext = () => {
    setActiveIndex(prev => (prev + 1) % attachment.items.length);
  };

  const handlePrev = () => {
    setActiveIndex(prev => (prev - 1 + attachment.items.length) % attachment.items.length);
  };

  const currentItem = attachment.items[activeIndex];

  return (
    <div className="carousel-container">
      <div className="carousel-card">
        {currentItem.imageUrl && <img src={currentItem.imageUrl} alt={currentItem.title} className="carousel-image" />}
        <h3 className="carousel-title">{currentItem.title}</h3>
        <p className="carousel-description">{currentItem.description}</p>
        {currentItem.actionUrl && (
          <a href={currentItem.actionUrl} target="_blank" rel="noopener noreferrer" className="carousel-action">
            View Details
          </a>
        )}
      </div>
      <div className="carousel-controls">
        <button onClick={handlePrev} disabled={attachment.items.length <= 1}>&larr;</button>
        <span>{activeIndex + 1} / {attachment.items.length}</span>
        <button onClick={handleNext} disabled={attachment.items.length <= 1}>&rarr;</button>
      </div>
    </div>
  );
};

export const CustomMessageRenderer: React.FC<{ message: Message }> = ({ message }) => {
  const isBot = message.direction === 'inbound';
  const carouselAttachment = message.attachments?.find(
    (att) => att.type === AttachmentType.CAROUSEL
  ) as CarouselAttachment | undefined;

  return (
    <div className={`message-bubble ${isBot ? 'bot' : 'user'}`}>
      {carouselAttachment ? (
        <CarouselRenderer attachment={carouselAttachment} />
      ) : (
        <MarkdownRenderer content={message.content || ''} />
      )}
      <span className="message-timestamp">
        {new Date(message.timestamp).toLocaleTimeString()}
      </span>
    </div>
  );
};

The renderer checks for carousel attachments first. If a carousel exists, it renders the interactive component. Otherwise, it falls back to markdown parsing. The remarkGfm plugin enables tables, task lists, and strikethrough syntax that Genesys Cloud bot frameworks frequently emit. You must sanitize markdown input in production environments to prevent XSS vulnerabilities. The carousel component maintains local state for navigation but does not block the main rendering thread.

Step 3: Implement Media Fallback and Scroll Synchronization

Media attachments such as images or videos can fail to load due to network restrictions or expired CDN tokens. The SDK provides url and thumbnailUrl fields in the attachment payload. You must attach an error handler to media elements to swap the source to the thumbnail preview. Scroll synchronization requires tracking which messages enter the viewport and sending acknowledgment frames to the WebSocket server.

import { useEffect, useRef, useState } from 'react';
import { Attachment, AttachmentType } from '@genesys/web-messaging-client';

interface MediaFallbackProps {
  attachment: Attachment;
}

export const MediaFallbackRenderer: React.FC<MediaFallbackProps> = ({ attachment }) => {
  const [isError, setIsError] = useState(false);
  const [activeUrl, setActiveUrl] = useState(attachment.url);

  const handleError = () => {
    if (attachment.thumbnailUrl && !isError) {
      setActiveUrl(attachment.thumbnailUrl);
      setIsError(true);
    }
  };

  if (attachment.type === AttachmentType.IMAGE) {
    return (
      <img 
        src={activeUrl} 
        alt="Media attachment" 
        onError={handleError}
        className="media-attachment"
      />
    );
  }

  if (attachment.type === AttachmentType.VIDEO) {
    return (
      <video controls onError={handleError} className="media-attachment">
        <source src={activeUrl} type="video/mp4" />
        Your browser does not support the video tag.
      </video>
    );
  }

  return null;
};

export function useScrollAcknowledgment(
  messages: Message[],
  acknowledgeMessage: (id: string) => void
) {
  const messageRefs = useRef<Map<string, HTMLDivElement>>(new Map());
  const observerRef = useRef<IntersectionObserver | null>(null);

  useEffect(() => {
    if (observerRef.current) {
      observerRef.current.disconnect();
    }

    observerRef.current = new IntersectionObserver(
      (entries) => {
        entries.forEach(entry => {
          if (entry.isIntersecting) {
            const messageId = entry.target.getAttribute('data-message-id');
            if (messageId) {
              acknowledgeMessage(messageId);
              observerRef.current?.unobserve(entry.target);
            }
          }
        });
      },
      { threshold: 0.5 }
    );

    return () => {
      observerRef.current?.disconnect();
    };
  }, [acknowledgeMessage]);

  const setRef = (element: HTMLDivElement | null, messageId: string) => {
    if (element) {
      messageRefs.current.set(messageId, element);
      observerRef.current?.observe(element);
    }
  };

  return { setRef, messageRefs };
}

The MediaFallbackRenderer swaps the primary URL to the thumbnail URL on the first error event. This prevents broken image icons and maintains layout stability. The useScrollAcknowledgment hook uses the Intersection Observer API to detect when a message enters the viewport. When intersection occurs, it calls the SDK’s acknowledgeMessage method and stops observing that element. This pattern ensures accurate read receipts without flooding the WebSocket connection with duplicate acknowledgments.

Complete Working Example

The following module combines authentication, client initialization, custom rendering, and scroll synchronization into a single runnable React component. Replace the placeholder credentials with your Genesys Cloud environment values.

import React, { useEffect, useRef } from 'react';
import { fetchWebMessagingJwt } from './auth';
import { useWebMessagingClient } from './client';
import { CustomMessageRenderer, MediaFallbackRenderer } from './renderers';
import { useScrollAcknowledgment } from './scroll';

interface WebChatWidgetProps {
  deploymentId: string;
  region: string;
  clientId: string;
  clientSecret: string;
  userId?: string;
  userDisplayName?: string;
}

export const WebChatWidget: React.FC<WebChatWidgetProps> = ({
  deploymentId,
  region,
  clientId,
  clientSecret,
  userId,
  userDisplayName,
}) => {
  const [jwt, setJwt] = useState<string | null>(null);
  const [loading, setLoading] = useState(true);

  useEffect(() => {
    const init = async () => {
      try {
        const token = await fetchWebMessagingJwt(clientId, clientSecret, deploymentId, region);
        setJwt(token);
      } catch (error) {
        console.error('Authentication failed:', error);
      } finally {
        setLoading(false);
      }
    };
    init();
  }, [clientId, clientSecret, deploymentId, region]);

  if (loading || !jwt) {
    return <div className="chat-widget-loading">Initializing secure connection...</div>;
  }

  return (
    <ChatContainer 
      deploymentId={deploymentId} 
      region={region} 
      jwt={jwt} 
      userId={userId} 
      userDisplayName={userDisplayName} 
    />
  );
};

interface ChatContainerProps {
  deploymentId: string;
  region: string;
  jwt: string;
  userId?: string;
  userDisplayName?: string;
}

const ChatContainer: React.FC<ChatContainerProps> = ({
  deploymentId,
  region,
  jwt,
  userId,
  userDisplayName,
}) => {
  const { messages, acknowledgeMessage } = useWebMessagingClient({
    deploymentId,
    region,
    jwt,
    userId,
    userIdentity: userDisplayName,
  });

  const { setRef } = useScrollAcknowledgment(messages, acknowledgeMessage);
  const messagesEndRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' });
  }, [messages]);

  return (
    <div className="chat-widget-container">
      <div className="message-list" style={{ maxHeight: '500px', overflowY: 'auto' }}>
        {messages.map((msg) => (
          <div
            key={msg.id}
            data-message-id={msg.id}
            ref={(el) => setRef(el, msg.id)}
            className="message-row"
          >
            {msg.attachments?.some(att => ['IMAGE', 'VIDEO'].includes(att.type)) ? (
              <MediaFallbackRenderer attachment={msg.attachments[0]} />
            ) : (
              <CustomMessageRenderer message={msg} />
            )}
          </div>
        ))}
        <div ref={messagesEndRef} />
      </div>
    </div>
  );
};

This component handles the full lifecycle from JWT acquisition to WebSocket connection, message interception, custom rendering, and scroll synchronization. You must configure your tsconfig.json to enable jsx: react-jsx and install the required dependencies before running the module.

Common Errors & Debugging

Error: 401 Unauthorized on JWT Endpoint

The Genesys Cloud API rejects the request when the OAuth token lacks the webmessaging:send scope or when the client credentials are misconfigured. Verify that your OAuth application in the Genesys Cloud admin console has the correct scopes assigned. Ensure the grant_type parameter matches client_credentials.

Error: WebSocket Connection Refused or 403 Forbidden

The Web Messaging client rejects connections when the JWT expires or when the deployment ID does not match the token payload. The SDK emits a DISCONNECTED event with a status code. Implement a token refresh timer that regenerates the JWT thirty seconds before the expiresAt timestamp and calls client.reconnect() with the new token.

Error: Markdown Rendering Blocks Layout

Unsanitized markdown payloads can inject unbounded CSS or script tags that break the message container. The react-markdown library strips dangerous HTML by default. If you require custom HTML support, integrate dompurify to sanitize the output before rendering. Configure the urlTransform option in react-markdown to enforce https protocols for all links.

Error: Acknowledgment Messages Fail Silently

The acknowledgeMessage method throws when the WebSocket connection drops during high network latency. Wrap the acknowledgment call in a try-catch block and implement a queue that retries failed acknowledgments when the CONNECTED event fires. Do not acknowledge the same message ID multiple times, as the server returns a 400 Bad Request for duplicate receipts.

Error: Carousel Attachments Render as Plain Text

The SDK normalizes carousel payloads into a JSON structure within the content field for older bot versions. Parse the content string with JSON.parse and validate the schema before rendering the carousel component. Check for try-catch failures and fall back to raw text rendering when the structure does not match the expected carousel format.

Official References

• Genesys Cloud Web Messaging REST API Documentation
• Web Messaging Client SDK Reference (v2)
• OAuth 2.0 Client Credentials Flow
• Intersection Observer API Specification
• React Markdown Documentation