Active Admin is a Ruby Gem.

gem 'activeadmin'

More accurately, it's a Rails Engine that can be injected into your existing Ruby on Rails application.

Setting up Active Admin

After installing the gem, you need to run the generator. By default we use Devise, and the generator creates an AdminUser model. If you want to create a different model (or modify an existing one for use with Devise) you can pass it as an argument. If you want to skip Devise configuration entirely, you can pass --skip-users.

rails g active_admin:install              # creates the AdminUser class
rails g active_admin:install User         # creates / edits the class for use with Devise
rails g active_admin:install --skip-users # skips Devise install

The generator adds these core files, among others:


Now, migrate your database and start the server:

rake db:migrate
rails server

Visit http://localhost:3000/admin and log in as the default user:

  • User:
  • Password: password

Voila! You're on your brand new Active Admin dashboard.

To register an existing model with Active Admin:

rails generate active_admin:resource MyModel

This creates a file at app/admin/my_model.rb to set up the UI; refresh your browser to see it.


When upgrading to a new version, it's a good idea to check the CHANGELOG.

To update the JS & CSS assets:

rails generate active_admin:assets

You should also sync these files with their counterparts in the AA source code:

  • app/admin/dashboard.rb ~>
  • config/initializers/active_admin.rb ~>

Gem compatibility


If you use will_paginate in your app, you need to configure an initializer for Kaminari to avoid conflicts.

# config/initializers/kaminari.rb
Kaminari.configure do |config|
  config.page_method_name = :per_page_kaminari


If you're getting the error wrong number of arguments (6 for 4..5), read #2703.

Copyright 2011 Greg Bell and VersaPay