diff --git a/app/controllers/admin/groups_controller.rb b/app/controllers/admin/groups_controller.rb
index 5de992cee60..6f4df60047f 100644
--- a/app/controllers/admin/groups_controller.rb
+++ b/app/controllers/admin/groups_controller.rb
@@ -55,7 +55,10 @@ class Admin::GroupsController < Admin::AdminController
 
     # group rename is ignored for automatic groups
     group.name = group_params[:name] if group_params[:name] && !group.automatic
-    save_group(group) { |g| GroupActionLogger.new(current_user, g).log_change_group_settings }
+    save_group(group) do |group|
+      GroupActionLogger.new(current_user, group).log_change_group_settings
+      DiscourseEvent.trigger(:group_updated, group)
+    end
   end
 
   def save_group(group)
diff --git a/app/controllers/categories_controller.rb b/app/controllers/categories_controller.rb
index aaaf1ec7bd6..e2fa98fda1a 100644
--- a/app/controllers/categories_controller.rb
+++ b/app/controllers/categories_controller.rb
@@ -149,6 +149,7 @@ class CategoriesController < ApplicationController
       old_permissions = cat.permissions_params
 
       if result = cat.update(category_params)
+        DiscourseEvent.trigger(:category_updated, cat)
         Scheduler::Defer.later "Log staff action change category settings" do
           @staff_action_logger.log_category_settings_change(@category, category_params, old_permissions)
         end
@@ -165,6 +166,7 @@ class CategoriesController < ApplicationController
     custom_slug = params[:slug].to_s
 
     if custom_slug.present? && @category.update_attributes(slug: custom_slug)
+      DiscourseEvent.trigger(:category_updated, @category)
       render json: success_json
     else
       render_json_error(@category)
diff --git a/app/controllers/groups_controller.rb b/app/controllers/groups_controller.rb
index 8233d5ab99e..6d370477456 100644
--- a/app/controllers/groups_controller.rb
+++ b/app/controllers/groups_controller.rb
@@ -137,6 +137,7 @@ class GroupsController < ApplicationController
 
     if group.update_attributes(group_params)
       GroupActionLogger.new(current_user, group).log_change_group_settings
+      DiscourseEvent.trigger(:group_updated, group)
 
       render json: success_json
     else
diff --git a/app/jobs/regular/emit_web_hook_event.rb b/app/jobs/regular/emit_web_hook_event.rb
index cc80fcebb2f..a893b49689a 100644
--- a/app/jobs/regular/emit_web_hook_event.rb
+++ b/app/jobs/regular/emit_web_hook_event.rb
@@ -50,6 +50,18 @@ module Jobs
       args[:payload] = WebHookUserSerializer.new(user, scope: guardian, root: false).as_json
     end
 
+    def setup_group(args)
+      group = Group.find(args[:group_id])
+      return if group.blank?
+      args[:payload] = WebHookGroupSerializer.new(group, scope: guardian, root: false).as_json
+    end
+
+    def setup_category(args)
+      category = Category.find(args[:category_id])
+      return if category.blank?
+      args[:payload] = WebHookCategorySerializer.new(category, scope: guardian, root: false).as_json
+    end
+
     def ping_event?(event_type)
       event_type.to_s == 'ping'.freeze
     end
diff --git a/app/models/category.rb b/app/models/category.rb
index b2b7242873d..426da630adb 100644
--- a/app/models/category.rb
+++ b/app/models/category.rb
@@ -61,6 +61,9 @@ class Category < ActiveRecord::Base
   after_update :rename_category_definition, if: :saved_change_to_name?
   after_update :create_category_permalink, if: :saved_change_to_slug?
 
+  after_commit :trigger_category_created_event, on: :create
+  after_commit :trigger_category_destroyed_event, on: :destroy
+
   belongs_to :parent_category, class_name: 'Category'
   has_many :subcategories, class_name: 'Category', foreign_key: 'parent_category_id'
 
@@ -508,6 +511,16 @@ SQL
   def subcategory_list_includes_topics?
     subcategory_list_style.end_with?("with_featured_topics")
   end
+
+  def trigger_category_created_event
+    DiscourseEvent.trigger(:category_created, self)
+    true
+  end
+
+  def trigger_category_destroyed_event
+    DiscourseEvent.trigger(:category_destroyed, self)
+    true
+  end
 end
 
 # == Schema Information
diff --git a/app/models/group.rb b/app/models/group.rb
index 5d8e84436ec..d8fc3dd1916 100644
--- a/app/models/group.rb
+++ b/app/models/group.rb
@@ -35,6 +35,9 @@ class Group < ActiveRecord::Base
   after_save :expire_cache
   after_destroy :expire_cache
 
+  after_commit :trigger_group_created_event, on: :create
+  after_commit :trigger_group_destroyed_event, on: :destroy
+
   def expire_cache
     ApplicationSerializer.expire_cache_fragment!("group_names")
   end
@@ -580,6 +583,16 @@ class Group < ActiveRecord::Base
     self.member_of(groups, user).where("gu.owner")
   end
 
+  def trigger_group_created_event
+    DiscourseEvent.trigger(:group_created, self)
+    true
+  end
+
+  def trigger_group_destroyed_event
+    DiscourseEvent.trigger(:group_destroyed, self)
+    true
+  end
+
   protected
 
     def name_format_validator
diff --git a/app/models/web_hook_event_type.rb b/app/models/web_hook_event_type.rb
index d3596bfdaf5..a98bd5a99d0 100644
--- a/app/models/web_hook_event_type.rb
+++ b/app/models/web_hook_event_type.rb
@@ -2,6 +2,8 @@ class WebHookEventType < ActiveRecord::Base
   TOPIC = 1
   POST = 2
   USER = 3
+  GROUP = 4
+  CATEGORY = 5
 
   has_and_belongs_to_many :web_hooks
 
diff --git a/app/serializers/web_hook_category_serializer.rb b/app/serializers/web_hook_category_serializer.rb
new file mode 100644
index 00000000000..02708ad1546
--- /dev/null
+++ b/app/serializers/web_hook_category_serializer.rb
@@ -0,0 +1,12 @@
+class WebHookCategorySerializer < CategorySerializer
+
+  %i{
+    can_edit
+    notification_level
+  }.each do |attr|
+    define_method("include_#{attr}?") do
+      false
+    end
+  end
+
+end
diff --git a/app/serializers/web_hook_group_serializer.rb b/app/serializers/web_hook_group_serializer.rb
new file mode 100644
index 00000000000..c580451db88
--- /dev/null
+++ b/app/serializers/web_hook_group_serializer.rb
@@ -0,0 +1,12 @@
+class WebHookGroupSerializer < GroupShowSerializer
+
+  %i{
+    is_group_user
+    is_group_owner
+  }.each do |attr|
+    define_method("include_#{attr}?") do
+      false
+    end
+  end
+
+end
diff --git a/config/initializers/012-web_hook_events.rb b/config/initializers/012-web_hook_events.rb
index 7e29c2d3011..158d09e3f0f 100644
--- a/config/initializers/012-web_hook_events.rb
+++ b/config/initializers/012-web_hook_events.rb
@@ -42,3 +42,23 @@ end
     WebHook.enqueue_hooks(:user, user_id: user.id, event_name: event.to_s)
   end
 end
+
+%i(
+  group_created
+  group_updated
+  group_destroyed
+).each do |event|
+  DiscourseEvent.on(event) do |group|
+    WebHook.enqueue_hooks(:group, group_id: group.id, event_name: event.to_s)
+  end
+end
+
+%i(
+  category_created
+  category_updated
+  category_destroyed
+).each do |event|
+  DiscourseEvent.on(event) do |category|
+    WebHook.enqueue_hooks(:category, category_id: category.id, event_name: event.to_s)
+  end
+end
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index efe2378a125..2ace41e8cd2 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -2927,6 +2927,12 @@ en:
         user_event:
           name: "User Event"
           details: "When a user logs in, logs out, is created, approved or updated."
+        group_event:
+          name: "Group Event"
+          details: "When a group is created, updated or destroyed."
+        category_event:
+          name: "Category Event"
+          details: "When a category is created, updated or destroyed."
         delivery_status:
           title: "Delivery Status"
           inactive: "Inactive"
diff --git a/db/fixtures/007_web_hook_event_types.rb b/db/fixtures/007_web_hook_event_types.rb
index d91b5f09a1a..c3f8b8b1509 100644
--- a/db/fixtures/007_web_hook_event_types.rb
+++ b/db/fixtures/007_web_hook_event_types.rb
@@ -12,3 +12,13 @@ WebHookEventType.seed do |b|
   b.id = WebHookEventType::USER
   b.name = "user"
 end
+
+WebHookEventType.seed do |b|
+  b.id = WebHookEventType::GROUP
+  b.name = "group"
+end
+
+WebHookEventType.seed do |b|
+  b.id = WebHookEventType::CATEGORY
+  b.name = "category"
+end
diff --git a/spec/fabricators/web_hook_fabricator.rb b/spec/fabricators/web_hook_fabricator.rb
index d9354fb59e6..937fc0fee67 100644
--- a/spec/fabricators/web_hook_fabricator.rb
+++ b/spec/fabricators/web_hook_fabricator.rb
@@ -21,6 +21,9 @@ Fabricator(:wildcard_web_hook, from: :web_hook) do
   wildcard_web_hook true
 end
 
+Fabricator(:post_web_hook, from: :web_hook) do
+end
+
 Fabricator(:topic_web_hook, from: :web_hook) do
   transient topic_hook: WebHookEventType.find_by(name: 'topic')
 
@@ -36,3 +39,19 @@ Fabricator(:user_web_hook, from: :web_hook) do
     web_hook.web_hook_event_types = [transients[:user_hook]]
   end
 end
+
+Fabricator(:group_web_hook, from: :web_hook) do
+  transient group_hook: WebHookEventType.find_by(name: 'group')
+
+  after_build do |web_hook, transients|
+    web_hook.web_hook_event_types = [transients[:group_hook]]
+  end
+end
+
+Fabricator(:category_web_hook, from: :web_hook) do
+  transient category_hook: WebHookEventType.find_by(name: 'category')
+
+  after_build do |web_hook, transients|
+    web_hook.web_hook_event_types = [transients[:category_hook]]
+  end
+end
diff --git a/spec/jobs/emit_web_hook_event_spec.rb b/spec/jobs/emit_web_hook_event_spec.rb
index b7e1cca39d5..29be1e69250 100644
--- a/spec/jobs/emit_web_hook_event_spec.rb
+++ b/spec/jobs/emit_web_hook_event_spec.rb
@@ -56,9 +56,14 @@ describe Jobs::EmitWebHookEvent do
       stub_request(:post, "https://meta.discourse.org/webhook_listener")
         .to_return(body: 'OK', status: 200)
 
-      expect do
-        subject.execute(web_hook_id: post_hook.id, event_type: 'post', post_id: post.id)
-      end.to change(WebHookEvent, :count).by(1)
+      WebHookEventType.all.pluck(:name).each do |name|
+        web_hook_id = Fabricate("#{name}_web_hook").id
+        object_id = Fabricate(name).id
+
+        expect do
+          subject.execute(web_hook_id: web_hook_id, event_type: name, "#{name}_id": object_id)
+        end.to change(WebHookEvent, :count).by(1)
+      end
     end
 
     it 'skips silently on missing post' do
diff --git a/spec/models/category_spec.rb b/spec/models/category_spec.rb
index 9f756f394f1..51992b1ce56 100644
--- a/spec/models/category_spec.rb
+++ b/spec/models/category_spec.rb
@@ -368,6 +368,17 @@ describe Category do
     end
   end
 
+  describe 'new' do
+    subject { Fabricate.build(:category, user: Fabricate(:user)) }
+
+    it 'triggers a extensibility event' do
+      event = DiscourseEvent.track_events { subject.save! }.last
+
+      expect(event[:event_name]).to eq(:category_created)
+      expect(event[:params].first).to eq(subject)
+    end
+  end
+
   describe "update" do
     it "should enforce uniqueness of slug" do
       Fabricate(:category, slug: "the-slug")
@@ -384,14 +395,21 @@ describe Category do
       @category_id = @category.id
       @topic_id = @category.topic_id
       SiteSetting.shared_drafts_category = @category.id.to_s
-      @category.destroy
     end
 
     it 'is deleted correctly' do
+      @category.destroy
       expect(Category.exists?(id: @category_id)).to be false
       expect(Topic.exists?(id: @topic_id)).to be false
       expect(SiteSetting.shared_drafts_category).to be_blank
     end
+
+    it 'triggers a extensibility event' do
+      event = DiscourseEvent.track_events { @category.destroy }.first
+
+      expect(event[:event_name]).to eq(:category_destroyed)
+      expect(event[:params].first).to eq(@category)
+    end
   end
 
   describe 'latest' do
diff --git a/spec/models/group_spec.rb b/spec/models/group_spec.rb
index 20b1e242d14..255b1d245e2 100644
--- a/spec/models/group_spec.rb
+++ b/spec/models/group_spec.rb
@@ -411,17 +411,37 @@ describe Group do
     expect(g.usernames.split(",").sort).to eq usernames.split(",").sort
   end
 
-  it "correctly destroys groups" do
+  describe 'new' do
+    subject { Fabricate.build(:group) }
 
-    g = Fabricate(:group)
-    u1 = Fabricate(:user)
-    g.add(u1)
-    g.save!
+    it 'triggers a extensibility event' do
+      event = DiscourseEvent.track_events { subject.save! }.first
 
-    g.destroy
+      expect(event[:event_name]).to eq(:group_created)
+      expect(event[:params].first).to eq(subject)
+    end
+  end
 
-    expect(User.where(id: u1.id).count).to eq 1
-    expect(GroupUser.where(group_id: g.id).count).to eq 0
+  describe 'destroy' do
+    let(:user) { Fabricate(:user) }
+    let(:group) { Fabricate(:group, users: [user]) }
+
+    before do
+      group.add(user)
+    end
+
+    it "it deleted correctly" do
+      group.destroy!
+      expect(User.where(id: user.id).count).to eq 1
+      expect(GroupUser.where(group_id: group.id).count).to eq 0
+    end
+
+    it 'triggers a extensibility event' do
+      event = DiscourseEvent.track_events { group.destroy! }.first
+
+      expect(event[:event_name]).to eq(:group_destroyed)
+      expect(event[:params].first).to eq(group)
+    end
   end
 
   it "has custom fields" do
diff --git a/spec/requests/categories_controller_spec.rb b/spec/requests/categories_controller_spec.rb
new file mode 100644
index 00000000000..9934db2450a
--- /dev/null
+++ b/spec/requests/categories_controller_spec.rb
@@ -0,0 +1,24 @@
+require 'rails_helper'
+
+describe GroupsController do
+  let(:admin) { Fabricate(:admin) }
+  let(:category) { Fabricate(:category, user: admin) }
+
+  before do
+    category
+    sign_in(admin)
+  end
+
+  it "triggers a extensibility event" do
+    event = DiscourseEvent.track_events {
+      put "/categories/#{category.id}.json", params: {
+        name: 'hello',
+        color: 'ff0',
+        text_color: 'fff'
+      }
+    }.last
+
+    expect(event[:event_name]).to eq(:category_updated)
+    expect(event[:params].first).to eq(category)
+  end
+end
diff --git a/spec/requests/groups_controller_spec.rb b/spec/requests/groups_controller_spec.rb
index 67e2afa1a29..5243092d817 100644
--- a/spec/requests/groups_controller_spec.rb
+++ b/spec/requests/groups_controller_spec.rb
@@ -450,6 +450,15 @@ describe GroupsController do
         expect(group.flair_color).to eq('BBB')
         expect(group.name).to eq('testing')
       end
+
+      it 'triggers a extensibility event' do
+        event = DiscourseEvent.track_events {
+          put "/groups/#{group.id}.json", params: { group: { flair_color: 'BBB' } }
+        }.last
+
+        expect(event[:event_name]).to eq(:group_updated)
+        expect(event[:params].first).to eq(group)
+      end
     end
 
     context "when user is not a group owner or admin" do