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React on Rails Basic Tutorial

Also see the example repo of React on Rails Tutorial With SSR, HMR fast refresh, and TypeScript

Updated for Ruby 2.7, Rails 7, React on Rails v13, and Shakapacker v7

This tutorial guides you through setting up a new or existing Rails app with React on Rails, demonstrating Rails + React + Redux + Server Rendering.

After finishing this tutorial you will get an application that can do the following (live on Heroku):


You can find it here:

By the time you read this, the latest may have changed. Be sure to check the versions here:

Table of Content:


Setting up your environment

Trying out React on Rails is super easy, so long as you have the basic prerequisites.

  • Ruby: We support all active Ruby versions but recommend using the latest stable Ruby version. Solutions like rvm or rbenv make it easy to have multiple Ruby versions on your machine.
  • Rails: We support Rails 6 and later.
  • Nodejs: We support all active Node versions but recommend using the latest LTS release of Nodejs for the longest support. Older inactive node versions might still work but is not guaranteed. We also recommend using nvm to ease using different node versions in different projects.
  • yarn: We use yarn classic as our node package manager.
  • You need to have either Overmind or Foreman as a process manager.

Create a new Ruby on Rails App

Then we need to create a fresh Rails application as follows.

First, be sure to run rails -v and check you are using Rails 5.1.3 or above. If you are using an older version of Rails, you'll need to install webpacker with react per the instructions here.

# For Rails 6.x
rails new test-react-on-rails --skip-javascript

# For Rails 7.x
rails new test-react-on-rails --skip-javascript

cd test-react-on-rails

Note: You can use --database=postgresql option to use Postgresql for the database.

Add the Shakapacker and react_on_rails gems

We recommend using the latest version of these gems. Otherwise, specify the exact versions of both the gem and npm packages. In other words, don't use the ^ or ~ in the version specifications.

bundle add react_on_rails --strict
bundle add shakapacker --strict

Note: The latest released React On Rails version is considered stable. Please use the latest version to ensure you get all the security patches and the best support.

Run the Shakapacker generator

bundle exec rails shakapacker:install

Commit all the changes so far to avoid getting errors in the next step.

git commit -am "Initial commit"

Alternatively, you can use --ignore-warnings in the next step.

Run the React on Rails Generator

rails generate react_on_rails:install

You will be prompted to approve changes in certain files. Press enter to proceed one by one or enter a to replace all configuration files required by the project. You can check the diffs before you commit to see what changed.

Note, using redux is no longer recommended as the basic installer uses React Hooks. If you want the redux install, run:

rails generate react_on_rails:install --redux

Setting up your environment variables

Add the following variable to your environment:


Then run the server with one of the following options:

Running the app

./bin/dev # For HMR
# or
./bin/dev-static # Without HMR, statically creating the bundles

Visit http://localhost:3000/hello_world and see your React On Rails app running!

HMR vs. React Hot Reloading

First, check that the hmr and the inline options are true in your config/shakapacker.yml file.

The basic setup will have HMR working with the default Shakapacker setup. The basic HMR, without a special React setup, will cause a full page refresh each time you save a file.

Deploying to Heroku

Create Your Heroku App

Assuming you can log in to and have logged into your shell for Heroku.

  1. Visit and create an app, say named my-name-react-on-rails:

Run this command that looks like this from your new Heroku app

heroku git:remote -a my-name-react-on-rails

Set heroku to use multiple buildpacks:

heroku buildpacks:set heroku/ruby
heroku buildpacks:add --index 1 heroku/nodejs

Swap out sqlite for postgres:

Heroku requires your app to use Postgresql. If you have not setup your app with Postgresql, you need to change your app settings to use this database.

Run the following command (in Rails 6+):

rails db:system:change --to=postgresql

If for any reason you want to do this process manually, run these two commands:

bundle remove sqlite3
bundle add pg

Now replace your database.yml file with this (assuming your app name is "ror").

default: &default
  adapter: postgresql
  host: localhost

  <<: *default
  database: ror_development

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
  <<: *default
  database: ror_test

  <<: *default
  database: ror_production

Then you need to setup postgres so you can run locally:

rake db:setup
rake db:migrate

Optionally you can add this line to your routes.rb. That way, your root page will go to the Hello World page for React On Rails.

root "hello_world#index"

Next, configure your app for Puma, per the instructions on Heroku.

Create ./Procfile with the following content. This is what Heroku uses to start your app.

web: bundle exec puma -C config/puma.rb

Note, newer versions of Rails create this file automatically. However, the docs on Heroku have something a bit different, so please make it conform to those docs. As of 2020-06-04, the docs looked like this:


workers Integer(ENV['WEB_CONCURRENCY'] || 2)
threads_count = Integer(ENV['RAILS_MAX_THREADS'] || 5)
threads threads_count, threads_count


rackup      DefaultRackup
port        ENV['PORT']     || 3000
environment ENV['RACK_ENV'] || 'development'

on_worker_boot do
  # Worker specific setup for Rails 4.1+
  # See:

Next, update your package.json to specify the version of yarn and node. Add this section:

  "engines": {
    "node": "16.19.0",
    "yarn": "1.22.4"

Then after all changes are done don't forget to commit them with git and finally, you can push your app to Heroku!

git add -A
git commit -m "Changes for Heroku"
git push heroku master

Then run:

heroku open

and you will see your live app and you can share this URL with your friends. Congrats!

Other features

Turning on Server Rendering

You can turn on server rendering by simply changing the prerender option to true:

<%= react_component("HelloWorld", props: @hello_world_props, prerender: true) %>

If you want to test this out with HMR, then you also need to add this line to your config/intializers/react_on_rails.rb

  config.same_bundle_for_client_and_server = true

More likely, you will create a different build file for server rendering. However, if you want to use the same file from the shakapack-dev-server, you'll need to add that line.

When you look at the source code for the page (right click, view source in Chrome), you can see the difference between non-server rendering, where your DIV containing your React looks like this:

<div id="HelloWorld-react-component-b7ae1dc6-396c-411d-886a-269633b3f604"></div>

versus with server rendering:

<div id="HelloWorld-react-component-d846ce53-3b82-4c4a-8f32-ffc347c8444a"><div data-reactroot=""><h3>Hello, <!-- -->Stranger<!-- -->!</h3><hr/><form><label for="name">Say hello to:</label><input type="text" id="name" value="Stranger"/></form></div></div>

For more details on server rendering, see:

ShakaCode recommends that you use /client for your client side app. This way a non-Rails, front-end developer can be at home just by opening up the /client directory.

  1. Move the directory:
mv app/javascript client
  1. Edit your /config/shakapacker.yml file. Change the default/source_path:
source_path: client

Using HMR with the shakapacker setup

Start the app using overmind start -f or foreman start -f

When you change and save a JSX file, the browser will automatically refresh!

So you get some basics from HMR with no code changes. If you want to go further, take a look at these links:

React on Rails will automatically handle disabling server rendering if there is only one bundle file created by the Webpack development server by shakapcker.

Custom IP & PORT setup (Cloud9 example)

In case you are running some custom setup with different IP or PORT you should also edit For example, to be able to run on free Cloud9 IDE we are putting IP and PORT 8080. The default generated file uses -p 3000.

web: rails s -p 8080 -b

Then visit

RubyMine performance tip

It's super important to exclude certain directories from RubyMine or else it will slow to a crawl as it tries to parse all the npm files.

  • Generated files, per the settings in your config/shakapacker.yml, which default to public/packs and public/packs-test
  • node_modules


Feedback is greatly appreciated! As are stars on github!

If you want personalized help, don't hesitate to get in touch with us at [email protected]. We offer React on Rails Pro and consulting so you can focus on your app and not on how to make Webpack plus Rails work optimally.