Realtime

Push data to connected clients the moment something changes — no polling, no refresh.

Database subscriptions

Subscribe to row changes on any table. The agent can wire this up from a prompt:

New chat messages should appear instantly without refreshing.

It sets up the subscription, handles cleanup on unmount, and updates the UI when new rows arrive.

Broadcast

Send custom events between clients. This is useful for cursor tracking, collaborative editing, or any feature where users need to see each other's actions:

const channel = supabase.channel('room-1');

// Send
channel.send({ type: 'broadcast', event: 'cursor', payload: { x, y } });

// Receive
channel.on('broadcast', { event: 'cursor' }, ({ payload }) => {
  updateCursor(payload);
});

Presence

Track who's online in real time. Presence data updates automatically when users join or leave — useful for active-user indicators, typing status, and collaborative features.