Notification API WebSocket: Handling 403 Forbidden on Conversation Events Subscription

NICE CXone API & Integrations
1

Looking for advice on establishing a stable WebSocket connection to the Genesys Cloud Notification API for real-time conversation updates.

I am building a Chrome extension that overlays CRM data based on agent activity. The extension uses chrome.runtime to manage background service workers and content scripts. My current implementation successfully retrieves an OAuth2 access token via a hidden iframe redirect flow. The token has the required webchat:read and conversation:read scopes.

However, when I attempt to open the WebSocket connection to wss://api.mypurecloud.com/api/v2/notification/events, I consistently receive a 403 Forbidden error during the initial handshake. The server closes the connection immediately after the upgrade request.

Here is the relevant JavaScript logic in my service worker:

const ws = new WebSocket(`wss://api.mypurecloud.com/api/v2/notification/events?access_token=${accessToken}`);

ws.onopen = () => {
 console.log('WebSocket connected');
 const subscription = {
 "eventType": "conversation",
 "payloadFields": ["id", "type", "state", "participants"]
 };
 ws.send(JSON.stringify(subscription));
};

ws.onerror = (err) => {
 console.error('WebSocket error:', err);
 // Logs: WebSocket error: Event {type: "error", target: WebSocket...}
};

I have verified the token is valid by calling GET /api/v2/users/me successfully in the same context. The issue seems isolated to the WebSocket upgrade. Is there a specific header requirement for the WebSocket connection that differs from standard REST calls?

I suspect cross-origin restrictions or missing headers might be interfering. Standard fetch requests work fine, but WebSocket does not support custom headers in the constructor. How do I pass the necessary authentication context securely without exposing the token in the URL query string, which feels like a security risk?

I need a robust pattern for handling this subscription in a browser environment. Any code examples for handling the 403 or alternative authentication methods for WebSockets would be appreciated.

2

TL;DR: Scope mismatch.

Make sure you are requesting notifications:subscribe in your OAuth grant, not just webchat:read. The Notification API endpoint /api/v2/analytics/events/realtime strictly enforces this scope for WebSocket authentication.

{
 "scope": "notifications:subscribe webchat:read"
}
3

Have you tried adding notifications:subscribe to your OAuth scopes? I deal with bulk data exports daily, and scope mismatches are the usual culprit for 403s on real-time endpoints. Ensure your grant includes both webchat:read and notifications:subscribe before attempting the WebSocket connection.

4

This is actually a known issue. The 403 is rarely about the WebSocket handshake itself; it is about the token validation failing against the subscription payload rules. You added notifications:subscribe, which is correct, but you are likely missing the specific resource scope for the entity you are subscribing to.

In Genesys Cloud, notifications:subscribe allows you to open the channel. It does not grant permission to see the events. If you are subscribing to conversations, you need conversations:read. If you are filtering by specific queues or agents, ensure the token has access to those resources. A common mistake in Chrome extensions is using a user token that lacks admin-level visibility if you are trying to subscribe to system-wide events.

Here is the correct subscription payload structure. Note the filters array. If your token lacks users:read or routing:queues:read, the server will reject the subscription with a 403 before the WebSocket even stabilizes.

{
 "topics": [
 "conversations"
 ],
 "filters": [
 {
 "field": "routing.queue.id",
 "operator": "eq",
 "value": "your-queue-id-here"
 }
 ]
}

If you are still getting 403s after adding conversations:read, check the token’s scope claim directly in the JWT decoder. The scope string must be space-separated.

Also, verify you are connecting to the correct region endpoint. Using api.mypurecloud.com when your org is in api.eu.purecloud.com will cause immediate auth failures.

  • Verify conversations:read scope is present
  • Check JWT region claim matches endpoint
  • Ensure subscription filter values exist and are accessible
  • Review Chrome extension service worker token refresh logic
5

Check your subscription payload; the SDK expects eventType not event_type.

const sub = new CreateSubscriptionRequest({
 eventType: "conversation:updated",
 filters: [{ name: "conversationId", value: "..." }]
});

Warning: The JS SDK strictly enforces camelCase for these model fields.