Collaboration

Collaboration runs on the same sync server. Turn it on for a sync client and pass that client to your editors:

import { createSyncClient } from "@fumadocs-editor/core/sync";
import { MdxEditor } from "@fumadocs-editor/ui";

declare const currentUser: { name: string };

const client = createSyncClient({
  collab: { user: { name: currentUser.name, color: "#7c3aed" } },
});

export function CollabEditor({ path }: { path: string }) {
  return <MdxEditor sync={{ client, path }} />;
}

• user is the name and color shown at your caret on other screens. collab: true joins as a guest.
• Yjs only loads when the first document opens.

Sync vs. collab

With collab on, the server holds one shared document per file and is the only one writing it to disk.

Sync and collab editors can open the same file. A sync save reaches collab editors like any other change on disk.

Restarts

The file is the only persistence. When the server restarts, the document is rebuilt from disk:

• edits made while the server was down are discarded
• edits made while only the network was down are kept and sent on reconnect
• a hard kill can lose the last second of edits; a normal shutdown saves them

Without MdxEditor

On a collab client, client.open joins the shared document. document.collab() returns its binding once synced:

• Pass the same components and syntax as your editor to client.open; the server parses the file with them.
• The binding is null until the first sync and while the server rebuilds the document. Rebuild your editor whenever document.subscribe fires.
• extensions() brings its own undo: turn off StarterKit's undoRedo.