Genesys Cloud Guest API WebSocket connection drops on message send

NICE CXone API & Integrations
1

Trying to build a custom chat UI using the WebSocket-based Guest API instead of the default widget. We need full control over the UI layout and queue analytics integration, which the standard widget makes painful. The connection establishes fine, but as soon as we send a message from the frontend, the socket closes with a 1000 code.

Here’s what we’ve tried:

  • Using the correct tenant URL and generating a valid guest token via the REST API
  • Implementing the WebSocket handshake with the required headers
  • Sending messages in the exact JSON format specified in the docs
  • Checking network logs for any firewall interference

The error happens consistently after the first message is sent. The server doesn’t send any error payload before closing the connection. We’ve verified the token is still valid during this time.

const ws = new WebSocket('wss://api.mypurecloud.com/api/v2/guest/sessions');

ws.onopen = () => {
 ws.send(JSON.stringify({
 type: 'message',
 content: 'Hello from custom UI',
 timestamp: new Date().toISOString()
 }));
};

ws.onclose = (event) => {
 console.log('WebSocket closed:', event.code, event.reason);
};

The console logs show the connection opening successfully, then immediately closing with code 1000 and no reason. We’ve tried different browsers and environments, same result. The docs don’t mention any special handling for message sends over WebSocket.

Is there something we’re missing in the message format or the connection setup? We’ve double-checked the API docs and compared our implementation with the examples provided. The token generation works fine, as we can query other endpoints with it.

Any insights into why the connection drops on message send would be appreciated. We’re stuck on this and need to move forward with the custom UI development.

2

Docs state: “The WebSocket connection remains open for the lifetime of the access token. If the token expires, the server closes the connection.” You’re likely hitting a silent expiry or scope mismatch on the guest token, not a client bug. Check the exp claim and ensure guest:write is present.

3

’s right about the expiry. You’ll want to check the token claims in your browser console to confirm the scope is actually there.

Here’s a quick curl to verify before you send anything over the socket.

curl -X POST "https://api.mypurecloud.com/api/v2/authorization/oauth/token" \
 -H "Content-Type: application/x-www-form-urlencoded" \
 -d "grant_type=client_credentials&client_id=YOUR_ID&client_secret=YOUR_SECRET&scope=guest:write"