Current limitations

What the pre-release of @folkways/realtime and Folkways don't do yet, and what is coming.

Today

Not on npm yet. Install from source until the first release.
One delivery type per topic rule. A topic rule in the dashboard has one class, so keep stream, kv and signal events on separate topics. See Topics and events.
History lives in memory on the node. Receipts report level: 'accepted'. If a node restarts, subscribers get a gap with reason 'epoch-lost' and continue; point lasting references at uid, which survives restarts.
No session resume. After a reconnect the SDK resubscribes from its saved positions. You still get every event once, but the node does the replay again.
Topic patterns, not wildcard subscriptions. Subscribe to concrete topics, such as chat/lobby. Patterns are for rules, permissions and client.on() filters.

Several delivery types in one topic. One chat/{room} topic carrying messages (stream), read receipts (kv) and typing (signal). The SDK already supports it; the dashboard's topic rules will follow.
Presence. Who is online in a topic and across the app.
Personal topics and direct messages. A topic per user that your backend can post to.
Member lists for private topics, with instant removal.
Revoking one user's access at once. Today a token lives until it expires (at most 15 minutes), or until you delete the signing key that signed it.

The SDK accepts options for some of these already (access and presence in topic definitions); they take effect once the feature is available.