This plugin was originally based on Acts as Taggable on Steroids by Jonathan Viney. It has evolved substantially since that point, but all credit goes to him for the initial tagging functionality that so many people have used.

For instance, in a social network, a user might have tags that are called skills, interests, sports, and more. There is no real way to differentiate between tags and so an implementation of this type is not possible with acts as taggable on steroids.

Enter Acts as Taggable On. Rather than tying functionality to a specific keyword (namely “tags”), acts as taggable on allows you to specify an arbitrary number of tag “contexts” that can be used locally or in combination in the same way steroids was used.


Rails 2.3.x

To use it, add it to your Gemfile:

gem 'acts-as-taggable-on', '~>2.1.0'

Rails 3.x

To use it, add it to your Gemfile:

gem 'acts-as-taggable-on', '~>2.2.0'

Post Installation

  1. rails generate acts_as_taggable_on:migration

  2. rake db:migrate


Acts As Taggable On uses RSpec for its test coverage. Inside the gem directory, you can run the specs for RoR 3.x with:

rake spec


class User < ActiveRecord::Base
  # Alias for <tt>acts_as_taggable_on :tags</tt>:
  acts_as_taggable_on :skills, :interests

@user = => "Bobby")
@user.tag_list = "awesome, slick, hefty"      # this should be familiar
@user.skill_list = "joking, clowning, boxing" # but you can do it for any context!
@user.skill_list                              # => ["joking","clowning","boxing"] as TagList

@user.tags # => [<Tag name:"awesome">,<Tag name:"slick">,<Tag name:"hefty">]
@user.skills # => [<Tag name:"joking">,<Tag name:"clowning">,<Tag name:"boxing">]

@frankie = User.create(:name => "Frankie", :skill_list => "joking, flying, eating")
User.skill_counts # => [<Tag name="joking" count=2>,<Tag name="clowning" count=1>...]

Finding Tagged Objects

Acts As Taggable On utilizes named_scopes to create an association for tags. This way you can mix and match to filter down your results, and it also improves compatibility with the will_paginate gem:

  class User < ActiveRecord::Base
    acts_as_taggable_on :tags, :skills
    scope :by_join_date, order("created_at DESC")

  User.tagged_with("awesome").by_date.paginate(:page => params[:page], :per_page => 20)

  # Find a user with matching all tags, not just one
  User.tagged_with(["awesome", "cool"], :match_all => :true)

  # Find a user with any of the tags:
  User.tagged_with(["awesome", "cool"], :any => true)

  # Find a user that not tags with awesome or cool:
  User.tagged_with(["awesome", "cool"], :exclude => true)

  # Find a user with any of tags based on context:
  User.tagged_with(['awesome, cool'], :on => :tags, :any => true).tagged_with(['smart', 'shy'], :on => :skills, :any => true)

You can also use :wild => true option along with :any or :exclude option. It will looking for %awesome% and %cool% in sql.

Tip: User.tagged_with([]) or '' will return [], but not all records.


You can find objects of the same type based on similar tags on certain contexts. Also, objects will be returned in descending order based on the total number of matched tags.

@bobby = User.find_by_name("Bobby")
@bobby.skill_list # => ["jogging", "diving"]

@frankie = User.find_by_name("Frankie")
@frankie.skill_list # => ["hacking"]

@tom = User.find_by_name("Tom")
@tom.skill_list # => ["hacking", "jogging", "diving"]

@tom.find_related_skills # => [<User name="Bobby">,<User name="Frankie">]
@bobby.find_related_skills # => [<User name="Tom">]
@frankie.find_related_skills # => [<User name="Tom">]

Dynamic Tag Contexts

In addition to the generated tag contexts in the definition, it is also possible to allow for dynamic tag contexts (this could be user generated tag contexts!)

@user = => "Bobby")
@user.set_tag_list_on(:customs, "same, as, tag, list")
@user.tag_list_on(:customs) # => ["same","as","tag","list"]
@user.tags_on(:customs) # => [<Tag name='same'>,...]
User.tagged_with("same", :on => :customs) # => [@user]

Tag Ownership

Tags can have owners:

class User < ActiveRecord::Base

class Photo < ActiveRecord::Base
  acts_as_taggable_on :locations

@some_user.tag(@some_photo, :with => "paris, normandy", :on => :locations)
@some_photo.locations_from(@some_user) # => ["paris", "normandy"]
@some_photo.owner_tags_on(@some_user, :locations) # => [#<ActsAsTaggableOn::Tag id: 1, name: "paris">...]
@some_photo.owner_tags_on(nil, :locations) # => Ownerships equivalent to saying @some_photo.locations

Tag cloud calculations

To construct tag clouds, the frequency of each tag needs to be calculated. Because we specified acts_as_taggable_on on the User class, we can get a calculation of all the tag counts by using User.tag_counts_on(:customs). But what if we wanted a tag count for an single user's posts? To achieve this we call tag_counts on the association:


A helper is included to assist with generating tag clouds.

Here is an example that generates a tag cloud.


module PostsHelper
  include ActsAsTaggableOn::TagsHelper


class PostController < ApplicationController
  def tag_cloud
    @tags = Post.tag_counts_on(:tags)


<% tag_cloud(@tags, %w(css1 css2 css3 css4)) do |tag, css_class| %>
  <%= link_to, { :action => :tag, :id => }, :class => css_class %>
<% end %>


.css1 { font-size: 1.0em; }
.css2 { font-size: 1.2em; }
.css3 { font-size: 1.4em; }
.css4 { font-size: 1.6em; }

Remove unused tags

If you would like to remove unused tag objects after removing taggings, add

ActsAsTaggableOn::Tag.remove_unused = true

to initializer file.


We have a long list of valued contributors. Check them all


  • Artem Kramarenko (artemk)


  • Michael Bleigh

Copyright © 2007-2011 Michael Bleigh ( and Intridea Inc. (, released under the MIT license