How to set up a current Clojure environment with a JDK, the Clojure CLI, deps.edn, REPL-friendly editors, and a practical first project workflow.
Setting up a Clojure development environment is less about collecting many tools and more about getting four things right:
Older setup guides often make Leiningen sound like the universal first step. That is no longer the best default. The current official toolchain is centered on the Clojure CLI, deps.edn, and, when needed, tools.build.
Clojure runs on the JVM, so the first dependency is a working JDK. The official Clojure downloads page notes that Clojure is compiled to Java 8 compatible bytecode, and newer Java runtimes load it just fine. In practice, most current teams should install a modern LTS JDK rather than hunting for an older version unless a specific project requires one.
The simplest check is:
1java -version
If that command fails, stop there and fix Java first. Nearly every later problem will be noise until the JDK is installed correctly.
The Clojure CLI is now the main official entry point for:
Install it from the official getting-started and CLI docs rather than from random blog posts. After installation, verify it works:
1clojure -e "(println :clojure-ok)"
If your setup is correct, this should print :clojure-ok.
For a new project, start with a small deps.edn file:
1{:paths ["src" "resources"]
2 :deps {org.clojure/clojure {:mvn/version "1.12.4"}}}
Then add a simple namespace:
1(ns hello.core)
2
3(defn -main []
4 (println "Hello, Clojure"))
You now have a project that is easier to reason about than a large generated template. That matters in Clojure because understanding the REPL, namespace loading, and classpath model is part of becoming productive.
The best Clojure development experience is interactive. The official editors guide is right to emphasize two things:
That means your editor should not be chosen only by syntax coloring or file browsing. It should support:
The official editors page highlights several strong options.
Emacs remains one of the strongest environments for Clojure when paired with CIDER and structural-editing support. It is especially attractive if you value REPL-driven exploration and a deeply customizable editor.
VS Code is often the easiest place for newer Clojure developers to start, especially with Calva and the surrounding language-server tooling. It gives a friendlier on-ramp while still supporting the live-evaluation style that makes Clojure productive.
IntelliJ can be a strong fit for teams that already live in the JVM ecosystem and want a workflow that feels familiar alongside Java or Kotlin work.
The best choice is the one that gets you into a live REPL and keeps you there. A beautiful editor without good Clojure evaluation support will slow down learning.
For new work, it helps to separate responsibilities:
deps.edn: dependency and execution workflowtools.build: explicit artifact creation when you need jars or release tasksThat distinction matters because many setup problems come from mixing historical tutorials with the current official toolchain.
Once Java and the CLI work, a good first-day workflow is:
deps.ednsrc directoryThis teaches the actual development loop much faster than spending an hour generating starter projects you do not yet understand.
Most setup issues come from a small set of causes:
clojure is not on the shell PATHWhen debugging environment problems, test the stack in order:
java -versionclojure -e "(println :ok)"That order avoids wasting time on editor settings before the command-line toolchain is healthy.
flowchart LR
A["Install JDK"] --> B["Install Clojure CLI"]
B --> C["Create deps.edn Project"]
C --> D["Open REPL-Aware Editor"]
D --> E["Connect to Live REPL"]
E --> F["Evaluate, Reload, and Iterate"]
The most important thing to notice is that the editor is not the first step and templates are not the center of the flow. The live REPL is.
deps.edn as the default project entry point for new work.