Realtime

WebSocket subscriptions for live updates when records change or system events occur.

Quick Start

1. Start Bakend:

bak start

2. Connect to the realtime endpoint:

ws://localhost:8080/api/realtime

3. Subscribe to a channel:

{ "action": "subscribe", "channel": "posts.created" }

4. Create or update a record via REST. The server pushes an event frame to subscribed clients.

See examples/realtime-demo for a working demo with a browser client.

Authentication

Anonymous connections work for public collections. For protected data, pass a JWT:

ws://localhost:8080/api/realtime?token=<access_token>

Obtain a token via POST /api/auth/login. Browser WebSocket APIs cannot set custom headers, so the query parameter is the recommended approach.

Subscribing

Send JSON text frames:

{ "action": "subscribe", "channel": "posts.created" }

Unsubscribe:

{ "action": "unsubscribe", "channel": "posts.created" }

Keep the connection alive:

{ "action": "ping" }

Channels

Collection Events

Subscribe to create, update, or delete events for any collection:

posts.created
posts.updated
posts.deleted

Use a wildcard to receive all CRUD events:

posts.*

Other Events

Category	Channels
Auth	auth.login, auth.logout, auth.register
Storage	storage.uploaded, storage.deleted
Functions	function.started, function.completed, function.failed
Jobs	job.started, job.completed, job.failed
System	system.collection.created

Permission Filtering

Collection events respect the same read permission as the REST API. If a collection requires authentication or ownership to read records, realtime delivery follows the same rules.

Non-collection events use safe payloads and are delivered to all subscribers of that channel.

Event Shape

Events match the internal Event Bus schema:

{
  "type": "event",
  "event": {
    "id": "evt_123",
    "type": "posts.created",
    "timestamp": "2026-06-08T12:00:00.000Z",
    "source": "collections",
    "payload": { "id": "rec_1", "title": "Hello" }
  }
}

See Events for the full event model.

Limits

• Maximum 50 subscriptions per connection
• No per-record channels in v0.1
• Single-process deployment (no clustering)

API Reference

Full protocol details: WebSocket API