Fulcro Developers Guide: Single-page full-stack web applications in clj/cljs

In other words, almost all of the real logic is already on the client, and unless there is a bug, our UI won’t cause a server error because it is pre-checking everything before sending it out. If your application can assume reasonably reliable networking and you write your server operations to be atomic then your error handling can be a relatively small amount of code. This function could update application state to show some kind of top-level modal dialog that describes the problem, possibly allows the user to submit application history (for support viewer) to your servers, and then re-initializes the application in some way.

Source: book.fulcrologic.com