Realtime

Subscribe to table changes, filter events, and use broadcast / presence channels.

Table changes

Enable realtime for a table in the dashboard Realtime page (installs a Postgres trigger), then subscribe with the anon key:

index.ts

const unsubscribe = voltbase.realtime.subscribe('products', (event) => {
  console.log(event.type, event.table, event.record);
});

unsubscribe();
// or
voltbase.realtime.unsubscribe('products');
voltbase.realtime.disconnect();

Filters

index.ts

voltbase.realtime.subscribe(
  'products',
  (event) => console.log(event.record),
  { event: 'INSERT', filter: { status: 'active' } },
);

Broadcast & presence

index.ts

const channel = voltbase.realtime.channel('room-1');

channel
  .on('broadcast', { event: 'cursor' }, ({ payload }) => {
    console.log('cursor', payload);
  })
  .on('presence', { event: 'sync' }, ({ state }) => {
    console.log('online', state);
  })
  .subscribe();

channel.send({ type: 'broadcast', event: 'cursor', payload: { x: 1, y: 2 } });
channel.track({ user: 'alice' });
channel.untrack();
channel.unsubscribe();

Presence is single-instance

Presence state lives in memory on one API process. It does not sync across multiple Railway replicas — use one instance (or add Redis later) for shared presence.