You can use multiple tabs but to have more than one write to the DB and not be overwritten relies on (online) sync.

The problem is that Watermelon assumes a consistent view of the entire database, so you can't have multiple writers - at least not without synchronous notifications from IndexedDB (not a thing), leader election (cannot be made reliable), or some design sacrifices. To be reconsidered in the future...

> WatermelonDB uses the LokiJS adapter which is an in memory database that regularly persists the data to IndexedDB either on interval, or when the browser tab is closed