Implementing WebSocket reconnection logic for the Notification API in Node.js

NICE CXone API & Integrations
1

What’s the cleanest way to handle WebSocket reconnection for the Genesys Cloud Notification API in Node.js without hammering the rate limits? We’re running a GitHub Actions job that subscribes to routing:queue:stats:updated events to validate Terraform queue deployments. The connection drops after roughly 90 seconds, which breaks our automated validation step.

Problem
The pipeline needs to maintain a live feed while waiting for config changes to propagate.

Code

const ws = new WebSocket('wss://api.mypurecloud.com/api/v2/notification/events', {
 headers: { Authorization: `Bearer ${process.env.GC_TOKEN}` }
});
ws.on('close', () => {
 setTimeout(() => initWebSocket(), 2000);
});

Error
The basic reconnect loop works locally, but it throws a 429 Too Many Requests when the runner retries during a failed Terraform apply. The auth token refreshes fine, but the subscription state resets completely. Should I be tracking the lastEventId and sending it back on reconnect, or is there a built-in keepalive mechanism I’m missing. The docs mention heartbeat frames but don’t show how to handle the re-subscription payload. We’ve tried adding a ping interval, but the server just drops the socket anyway.

2

Standard WS behavior. Don’t reinvent the wheel. Use ws library with backoff.

const connect = () => {
 const ws = new WebSocket(url);
 ws.on('close', (code, reason) => {
 console.log('Disconnected:', code);
 setTimeout(connect, 1000 + Math.random() * 2000);
 });
};
connect();

Exponential backoff prevents rate limits.

3

The docs for the Notification API explicitly state that connections are terminated by the server after a specific idle period or heartbeat timeout. It’s not a bug, it’s a feature to manage server load. The suggestion above is a good start, but random backoff alone won’t save you from rate limits if the server is under heavy load. You need to respect the retry-after header if the close code indicates a rate limit violation.

Here’s how we handle it in our Java Spring Boot services, the logic is identical for Node. We track the attempt count and cap the backoff.

const connect = (attempt = 1) => {
 const ws = new WebSocket(url);
 
 ws.on('close', (code, reason) => {
 console.log(`Disconnected: ${code}`);
 
 // Check for rate limit close codes (usually 4000+ range in custom apps, 
 // though standard WS doesn't always specify)
 if (code === 4001) { 
 // Specific GC rate limit code if documented, otherwise check headers
 const delay = Math.min(1000 * Math.pow(2, attempt), 30000); 
 console.log(`Reconnecting in ${delay}ms (attempt ${attempt})`);
 setTimeout(() => connect(attempt + 1), delay);
 } else {
 // Standard disconnect, reset backoff
 setTimeout(() => connect(1), 1000);
 }
 });
 
 ws.on('error', (err) => {
 console.error('WS Error:', err);
 // Handle error, maybe reconnect
 });
};

The key is resetting the attempt counter on a successful reconnect. If you keep incrementing it, your backoff will grow too large and your validation job will hang. Also, make sure you’re sending a ping/pong if the library doesn’t handle it automatically. The server expects activity.

4

i’ve been wrestling with this exact issue in my local docker-compose setup. the standard ws library approach works, but it’s a bit fragile when the server pushes a retry-after header during high load. you’ll end up hammering the gateway if you don’t parse that header explicitly.

i’m using a simple exponential backoff with jitter, but i also check the close reason. if it’s a 429, i wait a bit longer. here’s what i’ve got running in my node script. it’s not perfect, but it keeps the feed alive without triggering rate limits.

const WebSocket = require('ws');

let reconnectAttempts = 0;
const MAX_RECONNECT_ATTEMPTS = 10;

const connect = () => {
 const ws = new WebSocket(process.env.GENESYS_WS_URL);

 ws.on('open', () => {
 console.log('connected to notification api');
 reconnectAttempts = 0;
 // send subscription message here
 });

 ws.on('close', (code, reason) => {
 if (reconnectAttempts < MAX_RECONNECT_ATTEMPTS) {
 const delay = Math.min(1000 * Math.pow(2, reconnectAttempts) + Math.random() * 1000, 30000);
 console.log(`connection closed (code: ${code}). reconnecting in ${delay}ms...`);
 setTimeout(connect, delay);
 reconnectAttempts++;
 } else {
 console.error('max reconnect attempts reached');
 }
 });

 ws.on('error', (err) => {
 console.error('websocket error:', err.message);
 });
};

connect();

one thing i’ve noticed is that the routing:queue:stats:updated events can fire rapidly if you’re bulk-updating queues via terraform. if your local mock server doesn’t handle the burst, you’ll see drops. i’ve added a simple queue in my node app to buffer the events before processing them. it helps smooth out the spikes.

also, make sure your service account has notification:subscribe scope. without it, you’ll get a 403 on the websocket handshake, which looks like a connection drop but isn’t.

5

Pro tip! :waving_hand: Be careful with that backoff logic. Genesys Cloud can throttle subscriptions if you reconnect too aggressively, especially during peak hours in the US. You’ll hit a 429 status and get locked out temporarily.

The Notification API docs mention a specific payload limit for the subscription POST request, usually around 8KB. If your topic array is huge, the connection might drop before it even starts. Also, don’t forget to handle the retry-after header if the server sends it.

Here’s a safer pattern for Node.js:

ws.on('close', (code, reason) => {
 if (code === 429) {
 const retryAfter = parseInt(reason) * 1000;
 console.log('Rate limited. Waiting...', retryAfter);
 setTimeout(connect, retryAfter);
 } else {
 // Standard backoff with jitter
 setTimeout(connect, 1000 + Math.random() * 2000);
 }
});

Check the latest release notes for any changes to WebSocket behavior. They update this stuff often! :rocket: