Yeah you were mistaken, it's a full stack design. They recommend https://github.com/wilkerlucio/pathom for the connection. It's GraphQL done right, you write data "resolvers" on the backend, you declare very flexible graph queries on the front end -> this populates client DB and then fulcro uses that to render frontend.

Highly recommend reading through this section: https://book.fulcrologic.com/#FullStack