I wrote an event collector for SnowPlow in Clojure (https://github.com/snowplow/snowplow/tree/master/2-collectors/clojure-collector https://github.com/snowplow/

I wrote an event collector for SnowPlow in Clojure (https://github.com/snowplow/snowplow/tree/master/2-collectors/clojure-collector https://github.com/snowplow/snowplow/tree/master/2-collector...), and really enjoyed the experience. Leiningen is excellent, far better than any other build tool I've used, and Ring and Compojure were both great. My only grumble with Clojure is that nobody seems to document the types that their functions take and return. It's a PITA having to read through a whole chain of functions just to figure out the types which are passing through it.