They usually use a central server and last-writer-wins semantics. Figma for example https://www.figma.com/blog/how-figmas-multiplayer-technology-works/ https:/

They usually use a central server and last-writer-wins semantics. Figma for example https://www.figma.com/blog/how-figmas-multiplayer-technology-works/ https://www.figma.com/blog/how-figmas-multiplayer-technology... I've seen CF Durable Objects used quite a lot. There are other emerging patterns too: https://www.instantdb.com/ https://www.instantdb.com/