Teams choose Convex for the real-time features and then don't think about data modeling. The reactive magic works best when your schema is designed for it. We see tables that don't fit the document model, queries that would be simpler in SQL, and architectures that fight the platform instead of using it.

We also see over-reliance on the frontend. Convex makes it easy to call mutations from the browser. That doesn't mean all your logic should live there. Complex validation, multi-step workflows, and anything that shouldn't run on the client belongs in server functions—queries, mutations, and actions.

Another pattern: ignoring the transaction model. Every mutation in Convex is a transaction. That's powerful, but it means you need to think about what belongs in one atomic operation versus what should be scheduled work. Teams that treat it like a traditional API miss the consistency guarantees that make Convex worth using.