WordPress core's real-time collaboration (RTC) feature in the block editor uses Yjs to allow multiple users to edit simultaneously. Key points for plugin/theme developers: collaboration is automatically disabled when classic meta boxes are detected (migrate to registered post meta with show_in_rest: true to re-enable it); the sync.providers filter lets developers replace the default HTTP polling transport with alternatives like WebSockets or WebRTC; and plugins must consume post data directly from the WordPress data store via useSelect rather than copying it into local React state, to avoid stale or conflicting data across collaborators. Custom blocks with insertion side effects should also be made intentional and user-triggered to prevent unintended actions for all connected editors.
Table of contents
Collaboration is disabled when meta boxes are presentThe sync.providers filter: Customizing the sync transport layerCommon issues when building plugins compatible with real-time collaborationSort: