diff --git a/lib/gitlab/email/handler.rb b/lib/gitlab/email/handler.rb
index e08b5be8984..cebedb19dcc 100644
--- a/lib/gitlab/email/handler.rb
+++ b/lib/gitlab/email/handler.rb
@@ -1,20 +1,23 @@
-require 'gitlab/email/handler/create_merge_request_handler'
-require 'gitlab/email/handler/create_note_handler'
-require 'gitlab/email/handler/create_issue_handler'
-require 'gitlab/email/handler/unsubscribe_handler'
+# frozen_string_literal: true
 
 module Gitlab
   module Email
     module Handler
-      HANDLERS = [
-        UnsubscribeHandler,
-        CreateNoteHandler,
-        CreateMergeRequestHandler,
-        CreateIssueHandler
-      ].freeze
+      def self.handlers
+        @handlers ||= load_handlers
+      end
+
+      def self.load_handlers
+        [
+          UnsubscribeHandler,
+          CreateNoteHandler,
+          CreateMergeRequestHandler,
+          CreateIssueHandler
+        ]
+      end
 
       def self.for(mail, mail_key)
-        HANDLERS.find do |klass|
+        handlers.find do |klass|
           handler = klass.new(mail, mail_key)
           break handler if handler.can_handle?
         end
diff --git a/lib/gitlab/email/handler/base_handler.rb b/lib/gitlab/email/handler/base_handler.rb
index 0bba433d04b..35bb49ad19a 100644
--- a/lib/gitlab/email/handler/base_handler.rb
+++ b/lib/gitlab/email/handler/base_handler.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Email
     module Handler
diff --git a/lib/gitlab/email/handler/create_issue_handler.rb b/lib/gitlab/email/handler/create_issue_handler.rb
index fc8615afcae..64ed9e036ad 100644
--- a/lib/gitlab/email/handler/create_issue_handler.rb
+++ b/lib/gitlab/email/handler/create_issue_handler.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'gitlab/email/handler/base_handler'
 
 module Gitlab
diff --git a/lib/gitlab/email/handler/create_merge_request_handler.rb b/lib/gitlab/email/handler/create_merge_request_handler.rb
index 2316e58c3fc..a5bd70248af 100644
--- a/lib/gitlab/email/handler/create_merge_request_handler.rb
+++ b/lib/gitlab/email/handler/create_merge_request_handler.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'gitlab/email/handler/base_handler'
 require 'gitlab/email/handler/reply_processing'
 
diff --git a/lib/gitlab/email/handler/create_note_handler.rb b/lib/gitlab/email/handler/create_note_handler.rb
index 379b114e957..c7c573595fa 100644
--- a/lib/gitlab/email/handler/create_note_handler.rb
+++ b/lib/gitlab/email/handler/create_note_handler.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'gitlab/email/handler/base_handler'
 require 'gitlab/email/handler/reply_processing'
 
diff --git a/lib/gitlab/email/handler/reply_processing.rb b/lib/gitlab/email/handler/reply_processing.rb
index 38b1425364f..ff6b2c729b2 100644
--- a/lib/gitlab/email/handler/reply_processing.rb
+++ b/lib/gitlab/email/handler/reply_processing.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Email
     module Handler
diff --git a/lib/gitlab/email/handler/unsubscribe_handler.rb b/lib/gitlab/email/handler/unsubscribe_handler.rb
index 56751e4e41e..d2f617b868a 100644
--- a/lib/gitlab/email/handler/unsubscribe_handler.rb
+++ b/lib/gitlab/email/handler/unsubscribe_handler.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'gitlab/email/handler/base_handler'
 
 module Gitlab
diff --git a/spec/lib/gitlab/email/handler/create_issue_handler_spec.rb b/spec/lib/gitlab/email/handler/create_issue_handler_spec.rb
index 154ab4b3856..1d75e8cb5da 100644
--- a/spec/lib/gitlab/email/handler/create_issue_handler_spec.rb
+++ b/spec/lib/gitlab/email/handler/create_issue_handler_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'spec_helper'
 
 describe Gitlab::Email::Handler::CreateIssueHandler do
diff --git a/spec/lib/gitlab/email/handler/create_merge_request_handler_spec.rb b/spec/lib/gitlab/email/handler/create_merge_request_handler_spec.rb
index 43c6280f251..ace3104f36f 100644
--- a/spec/lib/gitlab/email/handler/create_merge_request_handler_spec.rb
+++ b/spec/lib/gitlab/email/handler/create_merge_request_handler_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'spec_helper'
 
 describe Gitlab::Email::Handler::CreateMergeRequestHandler do
diff --git a/spec/lib/gitlab/email/handler/create_note_handler_spec.rb b/spec/lib/gitlab/email/handler/create_note_handler_spec.rb
index 950a7dd7d6c..b1f48c15c21 100644
--- a/spec/lib/gitlab/email/handler/create_note_handler_spec.rb
+++ b/spec/lib/gitlab/email/handler/create_note_handler_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'spec_helper'
 
 describe Gitlab::Email::Handler::CreateNoteHandler do
diff --git a/spec/lib/gitlab/email/handler/unsubscribe_handler_spec.rb b/spec/lib/gitlab/email/handler/unsubscribe_handler_spec.rb
index ce160e11de2..b8660b133ec 100644
--- a/spec/lib/gitlab/email/handler/unsubscribe_handler_spec.rb
+++ b/spec/lib/gitlab/email/handler/unsubscribe_handler_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'spec_helper'
 
 describe Gitlab::Email::Handler::UnsubscribeHandler do
diff --git a/spec/lib/gitlab/email/handler_spec.rb b/spec/lib/gitlab/email/handler_spec.rb
index cedbfcc0d18..c651765dc0f 100644
--- a/spec/lib/gitlab/email/handler_spec.rb
+++ b/spec/lib/gitlab/email/handler_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'spec_helper'
 
 describe Gitlab::Email::Handler do
@@ -40,7 +42,7 @@ describe Gitlab::Email::Handler do
   end
 
   def ce_handlers
-    @ce_handlers ||= Gitlab::Email::Handler::HANDLERS.reject do |handler|
+    @ce_handlers ||= Gitlab::Email::Handler.handlers.reject do |handler|
       handler.name.start_with?('Gitlab::Email::Handler::EE::')
     end
   end