Performance

Message size

Keep messages small and serializable. Avoid large objects and circular references. If the data is big, store it somewhere shared and send an ID that references it.

Message frequency

For high-frequency updates (typing, dragging, live cursors):

• Use keepLatestMessage: true when only the newest value matters.
• Debounce at the source: send on a throttle, not on every keystroke.
• Give short-lived messages an expirationDuration so the log does not grow.

Batching

Outgoing messages are batched by default: calls to postMessage within a short window are grouped and sent as one array over the channel. This reduces cross-tab events during bursts (fast typing, bulk updates) and prevents message storms.

• batchingDelayMs (default 20) - the collection window. Set to 0 to disable batching and send every message immediately.
• excludedBatchMessageTypes (default []) - message types that always send immediately, even with batching on. Use it for urgent traffic like 'alert'.

const { postMessage } = useBroadcastChannel('editor', {
  batchingDelayMs: 50,
  excludedBatchMessageTypes: ['alert'],
});

Notes:

• Receivers handle single messages and batches automatically. If you also listen on the raw channel yourself, check Array.isArray(event.data).
• When the tab unmounts or the channel closes, unsent batched messages are flushed immediately.

Cleanup tuning

cleaningInterval and cleanupDebounceMs control how aggressively expired messages are swept. Under heavy load a modest cleanupDebounceMs batches sweeps; just keep it below cleaningInterval or expired messages may never be removed (details in Message lifecycle).