An example of plain Ring handler (for a blog post).

blog-ring-handler-plain.clj

(ns blog-ring.core
  (:require [ring.adapter.jetty :as jetty]))

(defn handler [request]
  {:status 200
   :headers {"Content-Type" "text/html"}
   :body "<h1>Hello, world!</h1>"})

(defn -main []
  (jetty/run-jetty handler
                   {:port 3000}))