plexus: my idea was to just extract the logic from the middleware part, probably it is already pretty much segregated apart from the wrap-* stuff: https://github.com/clojure-emacs/cider-nrepl/blob/master/src/cider/nrepl/middleware/spec.clj#L98

it is Clojure after all, it should be easy to do

Yeah, that’s one thing that has to be done for sure. It’s also a prerequisite for supporting things like the socket-repl and could also give a huge boost to even the plain repl, provided this new extracted library is included. For CIDER itself - there needs to be an abstraction layer hiding the details for the connection type (nREPL, socket, unrepl). Now that unrepl.el exists something like this should be relatively straightforward. There would be a need for some basic socket repl client, though.