&gt; Pretty much anything you&#x27;d like to do with CouchDB or MongoDB<p>Wekan is a Trello clone that uses MongoDB for storage. On Sandstorm, each board lives in a grain, so there ends up being one MongoDB per board. This works fine. The only thing stand-alone Wekan ever did that queried multiple boards at once is display the user&#x27;s list of all boards. On Sandstorm, displaying the user&#x27;s grain list is Sandstorm&#x27;s job, not Wekan&#x27;s -- and indeed, <i>usually</i> the user is more interested in seeing the list of <i>all</i> their grains rather than just the Wekan boards, so delegating this to Sandstorm is a UX win.<p>If that is not the kind of example you have in mind, then you really need to give a specific example.