diff --git a/LICENSE b/LICENSE
index 037ad7885..f36fc7c53 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,7 +1,11 @@
-The MIT License (MIT)
-
 Copyright (c) 2017-2021 Chatwoot Inc.
 
+Portions of this software are licensed as follows:
+
+* All content that resides under the "enterprise/" directory of this repository, if that directory exists, is licensed under the license defined in "enterprise/LICENSE".
+* All third party components incorporated into the Chatwoot Software are licensed under the original license provided by the owner of the applicable component.
+* Content outside of the above mentioned directories or restrictions above is available under the "MIT Expat" license as defined below.
+
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
diff --git a/app/controllers/api/v1/accounts/agents_controller.rb b/app/controllers/api/v1/accounts/agents_controller.rb
index a406e0cf3..a666d1a67 100644
--- a/app/controllers/api/v1/accounts/agents_controller.rb
+++ b/app/controllers/api/v1/accounts/agents_controller.rb
@@ -2,6 +2,7 @@ class Api::V1::Accounts::AgentsController < Api::V1::Accounts::BaseController
   before_action :fetch_agent, except: [:create, :index]
   before_action :check_authorization
   before_action :find_user, only: [:create]
+  before_action :validate_limit, only: [:create]
   before_action :create_user, only: [:create]
   before_action :save_account_user, only: [:create]
 
@@ -69,4 +70,8 @@ class Api::V1::Accounts::AgentsController < Api::V1::Accounts::BaseController
   def agents
     @agents ||= Current.account.users.order_by_full_name.includes({ avatar_attachment: [:blob] })
   end
+
+  def validate_limit
+    render_payment_required('Account limit exceeded. Upgrade to a higher plan') if agents.count >= Current.account.usage_limits[:agents]
+  end
 end
diff --git a/app/controllers/concerns/request_exception_handler.rb b/app/controllers/concerns/request_exception_handler.rb
index 1f96de737..51061017e 100644
--- a/app/controllers/concerns/request_exception_handler.rb
+++ b/app/controllers/concerns/request_exception_handler.rb
@@ -31,6 +31,10 @@ module RequestExceptionHandler
     render json: { error: message }, status: :unprocessable_entity
   end
 
+  def render_payment_required(message)
+    render json: { error: message }, status: :payment_required
+  end
+
   def render_internal_server_error(message)
     render json: { error: message }, status: :internal_server_error
   end
diff --git a/app/models/account.rb b/app/models/account.rb
index e23723611..657517c8d 100644
--- a/app/models/account.rb
+++ b/app/models/account.rb
@@ -6,6 +6,7 @@
 #  auto_resolve_duration :integer
 #  domain                :string(100)
 #  feature_flags         :integer          default(0), not null
+#  limits                :jsonb
 #  locale                :integer          default("en")
 #  name                  :string           not null
 #  settings_flags        :integer          default(0), not null
@@ -19,6 +20,7 @@ class Account < ApplicationRecord
   include FlagShihTzu
   include Reportable
   include Featurable
+  prepend_mod_with('Account')
 
   DEFAULT_QUERY_SETTING = {
     flag_query_mode: :bit_operator,
@@ -107,6 +109,13 @@ class Account < ApplicationRecord
     super || GlobalConfig.get('MAILER_SUPPORT_EMAIL')['MAILER_SUPPORT_EMAIL'] || ENV.fetch('MAILER_SENDER_EMAIL', 'Chatwoot <accounts@chatwoot.com>')
   end
 
+  def usage_limits
+    {
+      agents: ChatwootApp.max_limit,
+      inboxes: ChatwootApp.max_limit
+    }
+  end
+
   private
 
   def notify_creation
diff --git a/config/application.rb b/config/application.rb
index 074a2f744..0c7490dd7 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -13,8 +13,11 @@ module Chatwoot
     # Initialize configuration defaults for originally generated Rails version.
     config.load_defaults 6.0
 
-    config.autoload_paths << Rails.root.join('lib')
     config.eager_load_paths << Rails.root.join('lib')
+    config.eager_load_paths << Rails.root.join('enterprise/lib')
+    # rubocop:disable Rails/FilePath
+    config.eager_load_paths += Dir["#{Rails.root}/enterprise/app/**"]
+    # rubocop:enable Rails/FilePath
 
     # Settings in config/environments/* take precedence over those specified here.
     # Application configuration can go into files in config/initializers
diff --git a/config/initializers/01_inject_enterprise_edition_module.rb b/config/initializers/01_inject_enterprise_edition_module.rb
new file mode 100644
index 000000000..ecbcbe491
--- /dev/null
+++ b/config/initializers/01_inject_enterprise_edition_module.rb
@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+
+# original Authors: Gitlab
+# https://gitlab.com/gitlab-org/gitlab/-/blob/master/config/initializers/0_inject_enterprise_edition_module.rb
+#
+
+### Ref: https://medium.com/@leo_hetsch/ruby-modules-include-vs-prepend-vs-extend-f09837a5b073
+# Ancestors chain : it holds a list of constant names which are its ancestors
+#  example, by calling ancestors on the String class,
+#  String.ancestors => [String, Comparable, Object, PP::ObjectMixin, Kernel, BasicObject]
+#
+# Include: Ruby will insert the module into the ancestors chain of the class, just after its superclass
+# ancestor chain : [OriginalClass, IncludedModule, ...]
+#
+# Extend: class will actually import the module methods as class methods
+#
+# Prepend: Ruby will look into the module methods before looking into the class.
+# ancestor chain : [PrependedModule, OriginalClass, ...]
+########
+
+require 'active_support/inflector'
+
+module InjectEnterpriseEditionModule
+  def prepend_mod_with(constant_name, namespace: Object, with_descendants: false)
+    each_extension_for(constant_name, namespace) do |constant|
+      prepend_module(constant, with_descendants)
+    end
+  end
+
+  def extend_mod_with(constant_name, namespace: Object)
+    # rubocop:disable Performance/MethodObjectAsBlock
+    each_extension_for(
+      constant_name,
+      namespace,
+      &method(:extend)
+    )
+    # rubocop:enable Performance/MethodObjectAsBlock
+  end
+
+  def include_mod_with(constant_name, namespace: Object)
+    # rubocop:disable Performance/MethodObjectAsBlock
+    each_extension_for(
+      constant_name,
+      namespace,
+      &method(:include)
+    )
+    # rubocop:enable Performance/MethodObjectAsBlock
+  end
+
+  def prepend_mod(with_descendants: false)
+    prepend_mod_with(name, with_descendants: with_descendants)
+  end
+
+  def extend_mod
+    extend_mod_with(name)
+  end
+
+  def include_mod
+    include_mod_with(name)
+  end
+
+  private
+
+  def prepend_module(mod, with_descendants)
+    prepend(mod)
+
+    descendants.each { |descendant| descendant.prepend(mod) } if with_descendants
+  end
+
+  def each_extension_for(constant_name, namespace)
+    ChatwootApp.extensions.each do |extension_name|
+      extension_namespace =
+        const_get_maybe_false(namespace, extension_name.camelize)
+
+      extension_module =
+        const_get_maybe_false(extension_namespace, constant_name)
+
+      yield(extension_module) if extension_module
+    end
+  end
+
+  def const_get_maybe_false(mod, name)
+    mod&.const_defined?(name, false) && mod&.const_get(name, false)
+  end
+end
+
+Module.prepend(InjectEnterpriseEditionModule)
diff --git a/db/migrate/20211012135050_add_limits_to_accounts.rb b/db/migrate/20211012135050_add_limits_to_accounts.rb
new file mode 100644
index 000000000..8f5b28c25
--- /dev/null
+++ b/db/migrate/20211012135050_add_limits_to_accounts.rb
@@ -0,0 +1,5 @@
+class AddLimitsToAccounts < ActiveRecord::Migration[6.1]
+  def change
+    add_column :accounts, :limits, :jsonb, default: {}
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 10756d5c0..80e526555 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -52,6 +52,7 @@ ActiveRecord::Schema.define(version: 2021_12_08_085931) do
     t.integer "settings_flags", default: 0, null: false
     t.integer "feature_flags", default: 0, null: false
     t.integer "auto_resolve_duration"
+    t.jsonb "limits", default: {}
   end
 
   create_table "action_mailbox_inbound_emails", force: :cascade do |t|
diff --git a/enterprise/LICENSE b/enterprise/LICENSE
new file mode 100644
index 000000000..16d5eb94e
--- /dev/null
+++ b/enterprise/LICENSE
@@ -0,0 +1,36 @@
+The Chatwoot Enterprise license (the “Enterprise License”)
+Copyright (c) 2017-2021 Chatwoot Inc
+
+With regard to the Chatwoot Software:
+
+This software and associated documentation files (the "Software") may only be
+used in production, if you (and any entity that you represent) have agreed to,
+and are in compliance with, the Chatwoot Subscription Terms of Service, available
+at https://www.chatwoot.com/terms-of-service/ (the “Enterprise Terms”), or other
+agreement governing the use of the Software, as agreed by you and Chatwoot,
+and otherwise have a valid Chatwoot Enterprise License for for the
+correct number of user seats. Subject to the foregoing sentence, you are free to
+modify this Software and publish patches to the Software. You agree that Chatwoot
+and/or its licensors (as applicable) retain all right, title and interest in and
+to all such modifications and/or patches, and all such modifications and/or
+patches may only be used, copied, modified, displayed, distributed, or otherwise
+exploited with a valid Chatwoot Enterprise subscription for the correct
+number of user seats. Notwithstanding the foregoing, you may copy and modify
+the Software for development and testing purposes, without requiring a
+subscription. You agree that Chatwoot and/or its licensors (as applicable) retain
+all right, title and interest in and to all such modifications. You are not
+granted any other rights beyond what is expressly stated herein. Subject to the
+foregoing, it is forbidden to copy, merge, publish, distribute, sublicense,
+and/or sell the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+For all third party components incorporated into the Chatwoot Software, those
+components are licensed under the original license provided by the owner of the
+applicable component.
diff --git a/enterprise/app/models/enterprise/account.rb b/enterprise/app/models/enterprise/account.rb
new file mode 100644
index 000000000..84d72e0b3
--- /dev/null
+++ b/enterprise/app/models/enterprise/account.rb
@@ -0,0 +1,15 @@
+module Enterprise::Account
+  def usage_limits
+    {
+      agents: get_limits(:agents),
+      inboxes: get_limits(:inboxes)
+    }
+  end
+
+  private
+
+  def get_limits(limit_name)
+    config_name = "ACCOUNT_#{limit_name.to_s.upcase}_LIMIT"
+    self[:limits][limit_name.to_s] || GlobalConfig.get(config_name)[config_name] || ChatwootApp.max_limit
+  end
+end
diff --git a/enterprise/lib/enterprise.rb b/enterprise/lib/enterprise.rb
new file mode 100644
index 000000000..50fc8f63c
--- /dev/null
+++ b/enterprise/lib/enterprise.rb
@@ -0,0 +1,2 @@
+module Enterprise
+end
diff --git a/lib/chatwoot_app.rb b/lib/chatwoot_app.rb
new file mode 100644
index 000000000..842ecc479
--- /dev/null
+++ b/lib/chatwoot_app.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require 'pathname'
+
+module ChatwootApp
+  def self.root
+    Pathname.new(File.expand_path('..', __dir__))
+  end
+
+  def self.max_limit
+    100_000
+  end
+
+  def self.enterprise?
+    return if ENV.fetch('DISABLE_ENTERPRISE', false)
+
+    @enterprise ||= root.join('enterprise').exist?
+  end
+
+  def self.custom?
+    @custom ||= root.join('custom').exist?
+  end
+
+  def self.extensions
+    if custom?
+      %w[enterprise custom]
+    elsif enterprise?
+      %w[enterprise]
+    else
+      %w[]
+    end
+  end
+end
diff --git a/lib/custom_exceptions/account.rb b/lib/custom_exceptions/account.rb
index 84d57cd20..bd77c5a78 100644
--- a/lib/custom_exceptions/account.rb
+++ b/lib/custom_exceptions/account.rb
@@ -28,4 +28,10 @@ module CustomExceptions::Account
       I18n.t 'errors.signup.failed'
     end
   end
+
+  class PlanUpgradeRequired < CustomExceptions::Base
+    def message
+      I18n.t 'errors.plan_upgrade_required.failed'
+    end
+  end
 end
diff --git a/spec/enterprise/models/account_spec.rb b/spec/enterprise/models/account_spec.rb
new file mode 100644
index 000000000..6f0fa5aa7
--- /dev/null
+++ b/spec/enterprise/models/account_spec.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Account do
+  describe 'usage_limits' do
+    before do
+      create(:installation_config, name: 'ACCOUNT_AGENTS_LIMIT', value: 20)
+    end
+
+    let!(:account) { create(:account) }
+
+    it 'returns max limits from global config when enterprise version' do
+      expect(account.usage_limits).to eq(
+        {
+          agents: 20,
+          inboxes: ChatwootApp.max_limit
+        }
+      )
+    end
+
+    it 'returns max limits from account when enterprise version' do
+      account.update(limits: { agents: 10 })
+      expect(account.usage_limits).to eq(
+        {
+          agents: 10,
+          inboxes: ChatwootApp.max_limit
+        }
+      )
+    end
+  end
+end
diff --git a/spec/models/account_spec.rb b/spec/models/account_spec.rb
index 20ebf4bfd..03d8c8937 100644
--- a/spec/models/account_spec.rb
+++ b/spec/models/account_spec.rb
@@ -21,4 +21,12 @@ RSpec.describe Account do
   it { is_expected.to have_many(:kbase_portals).dependent(:destroy_async) }
   it { is_expected.to have_many(:kbase_categories).dependent(:destroy_async) }
   it { is_expected.to have_many(:teams).dependent(:destroy_async) }
+
+  describe 'usage_limits' do
+    let(:account) { create(:account) }
+
+    it 'returns ChatwootApp.max limits' do
+      expect(account.usage_limits).to eq({ agents: ChatwootApp.max_limit, inboxes: ChatwootApp.max_limit })
+    end
+  end
 end