Are you following the advice here? https://clojure.org/guides/repl/enhancing_your_repl_workflow#writing-repl-friendly-programs

Specifically, using #'handler instead of handler when starting your server and wrapping your handler with middleware. (hard to be more specific without seeing your code)

Yes, using #' seems to be what I’m missing. Thanks @U04V70XH6

If you care about performance very much, another option is to eta expand the function:

(fn ([request] (handler request))
    ([request s f] (handler request s f)))

You can call it a compiler trick

But what I like doing in the repl is to not bring up a server, but have a function that returns my handler then call it and apply the handler to a request built with ring.mock