One thing we do is to transform sub documents, which don’t need to be reactive, straight into the published doc. So we don’t need any method calls or an additional publish to connect relational data. I’m also wondering about scaring scaling issues. We’re running a Meteor app with ~1.5k concurrent users on a single VPS (+ one for the database) and also using individual subscriptions for each visitor. So only performance issues we had so far were missing/wrong indexes in the database.