Broadcast / Pub-Sub

Publish messages to named channels and deliver them to every online subscriber in real time. Ideal for announcements, live feeds, and collaborative features.

Core concepts

• Channel, A named topic string (e.g. announcements, room:lobby). Channels are created implicitly on first subscribe.
• Publisher, Any connected user can publish to a channel they're subscribed to.
• Subscriber, Users subscribe via a REST API call. Online subscribers receive broadcasts instantly over WebSocket.
• History, Messages are persisted with a 7-day TTL and retrievable via the REST API.

Quick start

// 1. Subscribe to a channel
await client.subscribeBroadcast('announcements');

// 2. Listen for incoming broadcasts
client.onBroadcast(msg => {
  console.log(msg.channelId, msg.publisherId, msg.plaintext);
});

// 3. Publish a message
const { broadcastId } = await client.publishBroadcast(
  'announcements',
  'Version 2.0 is live!'
);

// 4. Unsubscribe when done
await client.unsubscribeBroadcast('announcements');

BroadcastMessage object

Quotas & limits

Each plan defines a maximum number of broadcast channels and broadcast messages per month. See the pricing page for details.