TypeScript realtime

Connect and subscribe

const connection = await appUser.realtime.connect({
  webSocketFactory: (url, protocols) =>
    new WebSocket(url, [...protocols]),
});

const subscription = await connection.channels.subscribe({
  channelTypeKey: 'messaging',
  channelId: 'support-123',
});

const stop = subscription.onEvent((event) => {
  renderChannelEvent(event);
});

stop();
connection.close();

The connection obtains a one-use ticket, negotiates only vchat.realtime.v1, and is ready only after the strict connection.ready envelope. The subscription is authorized independently and starts from the server-acknowledged event baseline.

Delivery and sequence

• Delivery is at-least-once. Deduplicate by eventId.
• Track subscription.lastEventSequence for the accepted channel position.
• The SDK bounds in-memory deduplication; it does not persist exactly-once state.
• A refresh_required or stale subscription requires authoritative REST refresh before local continuity can be trusted.
• Compatible unknown future v1 event names are ignored safely while known ordering gaps trigger recovery.

Private user state

const stopPrivate = connection.onUserMessagingState((update) => {
  if (update.conversation.changed) {
    renderConversation(update.conversation.value);
  }
  if (update.unreadSummary.changed) {
    renderUnread(update.unreadSummary.value);
  }
});

Private conversation, unread, and thread state is visible only to the authenticated app user and uses independent version fences.

Presence and typing

An active channel subscription exposes connection-local presence and typing controllers. Presence watches exact bounded user IDs. Typing is scoped to the channel or a one-depth thread. Both are ephemeral and cleared on disconnect; neither is persisted or replayed as durable history.