You can create a template app with lein with: lein new compojure hello-world

handler.clj

(ns in-mem.handler
  (:require [compojure.core :refer :all]
            [compojure.route :as route]
            [ring.middleware.defaults :refer [wrap-defaults site-defaults]]))

(def start (slurp "../../tests/start.json"))
(defroutes app-routes
  (GET "/start" [] start)
  (route/not-found "Not Found"))

(def app
  (wrap-defaults app-routes site-defaults))

project.clj

(defproject hello-world "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :min-lein-version "2.0.0"
  :dependencies [[org.clojure/clojure "1.8.0"]
                 [compojure "1.5.1"]
                 [ring/ring-defaults "0.2.1"]]
  :plugins [[lein-ring "0.9.7"]]
  :jvm-opts ["-XX:+PreserveFramePointer"]  
  :ring {:handler in-mem.handler/app}
  :profiles
  {:dev {:dependencies [[javax.servlet/servlet-api "2.5"]
                        [ring/ring-mock "0.3.0"]]}})