Phase 10: Broadcast Model¶

Document Type: Technical Specification
Phase: 10 - Real-Time Subscriptions
Status: Active

Overview¶

Broadcast channels allow clients to send messages to each other without persisting to the database.

Channel Types¶

Public Channels¶

Anyone can join and broadcast:

realtime:broadcast:public-announcements

Private Channels¶

Require membership (checked via RLS):

realtime:broadcast:private-team-123

Message Format¶

Send¶

{
  "type": "broadcast",
  "topic": "realtime:broadcast:chat-room-1",
  "event": "message",
  "payload": {
    "text": "Hello, world!"
  }
}

Receive¶

{
  "type": "broadcast",
  "topic": "realtime:broadcast:chat-room-1",
  "event": "message",
  "payload": {
    "text": "Hello, world!",
    "sender_id": "user-uuid"
  }
}

Channel Isolation¶

• Channels are isolated by name
• No cross-channel message leakage
• RLS can restrict channel access

Rate Limiting¶