Both - libraries written in Clojure and wrapped versions of Java libraries. And because Java interop is pretty good, you can use Java libraries directly from C

Both - libraries written in Clojure and wrapped versions of Java libraries. And because Java interop is pretty good, you can use Java libraries directly from Clojure as well. I have written REST servers, data stream processing pipelines, hadoop jobs, react-based frontends, mobile apps, etc. in Clojure.