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The Project


This is an official template for a Fulcro starter project that might go on to become a production application. It includes a number of features that a beginner will not need for just playing with the library (full CI test setup, workspaces), but is simple enough that a beginner should have no real problem using it.

Beginners should therefore either use this template, or just generate simple play projects from the instructions in the Developer’s Guide.

Fulcro also has a Rapid Application Development add-on that makes building a production application faster and easier; however, a beginner should not start with RAD except to satisfy surface-level curiosity. RAD requires that you understand the core library (even though most of it uses convention and configuration over actual code). If you understand Fulcro and are working on a real production application then you should probably consider using the setup from the Fulcro RAD demo as starting point instead of this template.

RAD gives you a lot of leverage for a new project, and includes a number of pre-written patterns written in Fulcro. It includes very good HTML5 routing, form/report support. It does not limit your options, just expands what you have available by default.

About This Template

This template includes a server with a mock database and CSRF protection and a client with login. It also integrates Nubank Workspaces for a visual, interactive development environment for Fulcro components, which you can choose to use. Both backend Clojure and frontend ClojureScript REPLs are configured and started. There are also sample frontend tests.

The server code leverages Mount to make it easy to start and to reload changes - see the helper functions in src/dev/development.clj. Client hot code reloading is handled automatically by shadow-cljs.

The main project source is in src/main, the frontend code in .cljs files in app.* and app.ui.*.

Dependency Aliases:

You will want to enable the :dev dependency while developing this project. In IntelliJ this is in the "Clojure Deps" border tab window under "Aliases".

Quick Start

This is a manual to get started with this example project. It comes with helper npm run scripts pre-loaded, you can find them in the package.json file.

Typically you want to start the server and the main and/or workspaces (if you decided to use Nubank Workspaces) client builds. See below. You can simply start everything from the command line

git clone --depth 1 -o fulcro-template fulcro-app
cd fulcro-app

# The shadow-cljs compiler is a dependency.
yarn install

# 1. Start shadow-cljs frontend compilation server:
npx shadow-cljs server
# 2.: Visit the shadow-cljs compile server UI at http://localhost:9630
#     and enable the "main" and optionally "workspaces" builds
# 3. Start the backend server:
#    (Note: for proper development you will want to start it in a nREPL-based
#     REPL, see the detailed instructions for "The API Server" below.)
clj -A:dev -J-Dtrace -J-Dguardrails.enabled=true
user=> (require 'development)
user=> (in-ns 'development)
development=> (start)
# after modifications of the backend code run: `(restart)`
# 4. Visit the application at http://localhost:3000

# (Optional): Visit the Workspaces UI at http://localhost:3000/wslive.html
# (Optional): Run tests via `npm run client/test` and visit http://localhost:8022

The shadow-cljs compile server

You can find the UI of the frontend compile server here: http://localhost:9630 There you can kick off the compilation of the other targets.

Connect to the CLJS nREPL:

  1. Open and connect your nREPL to localhost:9000.

  2. Execute (shadow/repl :main). (you can select another target of course)

Backend Clojure nREPL:

The instructions provided above do not start a REPL server for the backend, only a simple interactive REPL session. See the The API Server section below to learn how to start the server from a nREPL REPL that you can connect your editor to.


If you choose to use Workspaces, you have two options, you can run them with the actual backend as described in the Quick Start above or you can run only the frontend part (communication with the backend will fail due to CSFR): npm run client/workspaces and visit http://localhost:8023

Have a look at src/workspaces.

Detailed instructions

Setting Up

The shadow-cljs compiler uses all js dependencies through NPM. If you use a library that is in cljsjs you will also have to add it to your package.json.

You also cannot compile this project until you install the ones it depends on already:

$ yarn install

Adding NPM Javascript libraries is as simple as adding them to your package.json file and requiring them! See the the Shadow-cljs User’s Guide for more information.

Development Mode

Shadow-cljs handles the client-side development build. The file src/main/app/client.cljs contains the code to start and refresh the client for hot code reload.

In general it is easiest just to run the compiler in server mode:

$ npx shadow-cljs server
INFO: XNIO version 3.3.8.Final
Nov 10, 2018 8:08:23 PM org.xnio.nio.NioXnio <clinit>
INFO: XNIO NIO Implementation Version 3.3.8.Final
shadow-cljs - HTTP server for :test available at http://localhost:8022
shadow-cljs - HTTP server for :workspaces available at http://localhost:8023
shadow-cljs - server version: 2.7.2
shadow-cljs - server running at http://localhost:9630
shadow-cljs - socket REPL running on port 51936
shadow-cljs - nREPL server started on port 9000

then navigate to the server URL (shown in this example as http://localhost:9630) and use the Builds menu to enable/disable whichever builds you want watched/running.

Shadow-cljs will also start a web server for any builds that configure one. This template configures one for workspaces (if running without the Clojure backend is enough for you), and one for tests:

See the server section below for working on the full-stack app itself.

Client REPL

The shadow-cljs compiler starts an nREPL. It is configured to start on port 9000 (in shadow-cljs.edn).

In IntelliJ: add a remote Clojure REPL configuration with host localhost and port 9000.


(shadow/repl :main)

will connect you to the REPL for a specific build (NOTE: Make sure you have a browser running the result, or your REPL won’t have anything to talk to!)

If you’re using CIDER see the Shadow-cljs User’s Guide and the comments in deps.edn for more information.

The API Server

In order to work with your main application you’ll want to start your own server that can also serve your application’s API.

Start a LOCAL clj nREPL in IntelliJ (using IntelliJ’s classpath with the dev alias selected in the Clojure Deps tab), or from the command line:

$ clj -A:dev -J-Dtrace -J-Dguardrails.enabled=true
user=> (require 'development)
development=> (in-ns 'development)
development=> (start)
development=> (stop)
development=> (restart) ; stop, reload server code, and go again
development=> (tools-ns/refresh) ; retry code reload if hot server reload fails

The -J-Dtrace adds a JVM argument that will enable performance tracing for Fulcro Inspect’s network tab so you can see how your resolvers and mutations are performing.

The -J-Dguardrails.enabled=true turns on guardrails instrumentation of guardrails spec’d functions, which is a wrapper of Clojure spec that makes instrumentation and production-time elision (for performance and size) much easier.

For real development, please use an editor that has REPL integration, like Cursive (recommended) or Spacemacs.

The URL to work on your application is then http://localhost:3000.

Hot code reload, preloads, and such are all coded into the javascript.


There is a preload file that is used on the development build of the application app.development-preload. You can add code here that you want to execute before the application initializes in development mode.

Fulcro Inspect

Fulcro inspect will preload on the development build of the main application and workspaces. You must install the plugin in Chrome from the Chrome store (free) to access it. It will add a Fulcro Inspect tab to the developer tools pane.


Tests are in src/test. Any test namespace ending in -test will be auto-detected.

└── app
    └── sample_test.cljc          spec runnable by client and server.

You can write plain deftest in here, and it is preconfigured to support the helper macros in fulcro-spec as well.

Running tests:

Clojure Tests

Typically you’ll just run your tests using the editor of choice (e.g. Run tests in namspace in IntelliJ).

The tests are also set up to run with Kaocha at the command line for your convenience and CI tools:

$ clj -A:dev:clj-tests --watch

See the Kaocha project for more details.

Clojurescript tests

The tests can be run in any number of browsers simply by navigating to the test URL that shadow-cljs outputs.

CI support is done through the ci-test build in shadow, and via Karma.

If you start the ci-tests build in Shadow-cljs, then you can also run cljs tests in a terminal "watch mode" with:

npx karma start

Of course, this make CLJS CI easy:

npx shadow-cljs compile ci-tests
npx karma start --single-run

Running all Tests Once

There is a UNIX Makefile that includes all of the CI commands as the default target. Just run:



Workspaces is a project by Nubank that is written in Fulcro, and has great support for developing in Fulcro. It is similar to devcards but has a more powerful user interface, integration with Fulcro Inspect, and much more.

The source directory for making additions to your workspace is src/workspaces.

Any namespace ending in -ws will be auto-detected and added to your workspace!

Standalone Runnable Jar (Production, with advanced optimized client js)

See tools deps projects like Depstar. You’ll need to make a release js build, optionally pre-compile your CLJ, and package it. We will likely add a demo of this process soon.


A sample project that could be used as a starting point for a Fulcro 3 project.







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