Live Updates

With the Sync plugin installed, the forum updates without page reloads. Without it, everything degrades to a plain server-rendered forum with no live markup at all, which is a perfectly good experience and the one search engines see.

realtime:
  enabled: true                # inert without the sync plugin
  new_replies_threshold: 5     # above this many unseen replies, show a load button
  presence:
    enabled: true
    heartbeat_seconds: 15

What updates live

• New replies appear in place inside a topic
• Reaction counts tick as people react
• Category listings raise a refresh bar when new topics arrive
• The notification bell and message envelope counts update
• Toast notifications slide in for replies, mentions and private messages

new_replies_threshold is a courtesy: below it, replies are inserted directly; above it, a load button appears instead, so a thread that is moving fast does not yank the page out from under a reader mid-sentence.

Presence and typing indicators

realtime:
  presence:
    enabled: true
    heartbeat_seconds: 15

Topic pages show who is viewing and who is typing. Clients send a heartbeat every heartbeat_seconds; raise it to reduce chatter on a large forum, lower it for a snappier feel on a small one.

Permission-aware channels

Live channels respect category permissions. A private category never broadcasts to outsiders: a user without read access is not subscribed to its channel and does not receive its events. Permissions are enforced server-side at subscribe time, not by filtering on the client.

Transports

Forum Pro picks the best transport available, in this order:

1. Mercure push

With the Sync Mercure plugin, updates arrive over server-sent events from a Mercure hub. This is the low-latency option and the one to use on a busy forum. Sync Mercure bundles the hub binary:

bin/plugin sync-mercure install
bin/plugin sync-mercure start

2. Polling

Without a push hub, clients fall back to polling automatically. No configuration is needed, and no functionality is lost. Latency is a few seconds instead of instant.

3. No live updates

Without the sync plugin, realtime is inert. Pages render server-side and stay as rendered until the reader reloads.

Admin → Forum → Status reports which transport is actually in use, which is the fastest way to confirm your Mercure hub is reachable.

In-page navigation

frontend:
  htmx: true

Moving between forum pages swaps the content region instead of doing a full page load. The implementation handles the parts that usually break in a partial-navigation setup:

• The back and forward buttons work
• Page titles update to match the new view
• Focus moves to the new content, so screen readers announce where you landed
• Live updates and the bell reconnect cleanly after every navigation

If your theme already ships htmx, Forum Pro stands down automatically rather than loading a second copy and fighting over the same attributes.

Set htmx: false for classic full page loads. Everything still works; navigation is just less smooth.

Troubleshooting