Adding Spree to an existing Rails application

Add Spree gems to your Gemfile

gem 'spree' # core and API
gem 'spree_backend' # Rails admin panel (optional)
gem 'spree_emails' # transactional emails (optional)
gem 'spree_sample' # dummy data like products, taxons, etc
gem 'spree_auth_devise', '~> 4.3' # Devise integration (optional)
gem 'spree_gateway', '~> 3.9' # payment gateways eg. Stripe, Braintree (optional)
gem 'spree_i18n', '~> 5.0' # translation files (optional)
# only needed for MacOS and Ruby 3.0
gem 'sassc', github: 'sass/sassc-ruby', branch: 'master'

Install gems

bundle install

Use the install generators to set up Spree

bin/rails g spree:install --user_class=Spree::User
bin/rails g spree:auth:install
bin/rails g spree_gateway:install
bin/rails javascript:install:esbuild
bin/rails g spree:backend:install

Installation options

By default, the installation generator (rails g spree:install) will run migrations as well as adding seed. This can be disabled using
bin/rails g spree:install --migrate=false --sample=false --seed=false
You can always perform any of these steps later by using these commands.
bin/rake railties:install:migrations
bin/rails db:migrate
bin/rails db:seed
bin/rake spree_sample:load

Mounting the Spree engine

When rails g spree:install is run inside an application, it will install Spree, mounting the Spree::Core::Engine component by inserting this line automatically into config/routes.rb:
mount Spree::Core::Engine, at: '/'
By default, all Spree routes will be available at the root of your domain. For example, if your domain is http://localhost:3000, Spree’s /products URL will be available at http://localhost:3000/products.
You can customize this simply by changing the :at specification in config/routes.rb to be something else. For example, if you would like Spree to be mounted at /shop, you can write this:
mount Spree::Core::Engine, at: `/shop`
The different parts of Spree (API, Admin) will be mounted there as well, eg. http://localhost:3000/shop/admin.

Use your existing authentication

Spree Auth Devise is the default authentication that comes with Spree but you can swap it for your own, please follow this guide

Hello, Spree Commerce

You now have a functional Spree application after running only a few commands!
To stop the webserver, hit Ctrl-C in the terminal window where it's running. In development mode, Spree does not generally require you to stop the server; changes you make in files will be automatically picked up by the server.

Logging Into the Admin Panel

The next thing you'll probably want to do is to log into the admin interface. Use your browser window to navigate to http://localhost:4000/admin. You can log in with the username [email protected] and password spree123.
Upon successful authentication, you should see the admin screen:
Feel free to explore some of the Admin Panel features that Spree has to offer and to verify that your installation is working properly.