Use of web components and polymer-project in Ruby on Rails projects

gem install polymer-rails -v 1.3.0



Want to get started with web components? Want to bring them into your Rails app? Easily build your own and use web components that are built by community in your Ruby on Rails Application. Polymer-rails helps you to do this:

  1. Adds polymer library to assets of your rails project.

  2. Allows you to easily import web component with <%= html_import_tag "my-component" %> helper.

  3. Allows you to import and package web components into assets pipeline, exactly as you would Javascript or CSS

Prefer using SASS or CoffeeSript?

Polymer-rails works well with compiling assets, such as CoffeeScript and Sass. You can easily use external stylesheet or script tag references in your web component <link rel="stylesheet" href="application.css"> for stylesheets and <script src="application.js"> for javascripts. This assets will be automatically compiled and required into component html file.

  • Note that if you're using sass or coffee precompilation, assets are required to use '.css.sass' and '' extensions.*


Polymer 2.0 is out!

  • Use 0.2.x versions of polymer-rails to work with Polymer versions 0.5.x
  • Use 1.0.x versions of polymer-rails to work with Polymer versions 1.0.x
  • Use 2.0.x versions of polymer-rails to work with Polymer versions 2.0.x

1.0 release is not compatible with the 0.5 APIs. For guidance on migrating an existing 0.5 elements to the 1.0 APIs, see the Migration guide.


Add this line to your application's Gemfile:

gem 'polymer-rails'

And then execute:

$ bundle

Or install it yourself as:

$ gem install polymer-rails



$ rails g polymer:install
  • This generator adds //= require webcomponentsjs/webcomponents-loader into application.js manifest file
  • Creates app/assets/components and application.html manifest file where you can include all your components.
  • Creates vendor/assets/components directory for third-party web components.

After running rails g polymer:install, add <%= html_import_tag 'application'%> line into your layout, to import web components manifest to your app.

Creating a component

$ rails g polymer:component <component-name>

This generates new <component-name> component directory and .html, .css, .js files of the same name under app/assets/components folder.

Add your component to .html manifest file after requiring polymer:

//= require polymer/polymer
//= require component-name/component-name

And you can use your component in Rails application!

Polymer core/paper elements

Polymer team is working on set of core element which you can learn more about here If you want to use them in your Rails application, checkout polymer-core-rails gem.

You may also be interested in Polymer paper elements, they are also available as polymer-paper-rails gem.


See example Rails application here

Source code can be found here

Learn more

You can check out or to see what components are already built by community.


  1. Fork it ( )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request