diff --git a/lib/copy_tuner_client/cache.rb b/lib/copy_tuner_client/cache.rb
index 07b3b3d..88552cb 100644
--- a/lib/copy_tuner_client/cache.rb
+++ b/lib/copy_tuner_client/cache.rb
@@ -18,6 +18,8 @@ def initialize(client, options)
       @mutex = Mutex.new
       @exclude_key_regexp = options[:exclude_key_regexp]
       @upload_disabled = options[:upload_disabled]
+      @ignored_keys = options.fetch(:ignored_keys, [])
+      @ignored_key_handler = options.fetch(:ignored_key_handler, -> (e) { raise e })
       @locales = Array(options[:locales]).map(&:to_s)
       # mutable states
       @blurbs = {}
@@ -44,6 +46,11 @@ def []=(key, value)
       return if @locales.present? && !@locales.member?(key.split('.').first)
       return if @upload_disabled
 
+      key_without_locale = key.split('.')[1..].join('.')
+      if @ignored_keys.include?(key_without_locale)
+        @ignored_key_handler.call(IgnoredKey.new("Ignored key: #{key_without_locale}"))
+      end
+
       lock do
         return if @blank_keys.member?(key) || @blurbs.key?(key)
 
diff --git a/lib/copy_tuner_client/version.rb b/lib/copy_tuner_client/version.rb
index c8d9400..addee7a 100644
--- a/lib/copy_tuner_client/version.rb
+++ b/lib/copy_tuner_client/version.rb
@@ -1,6 +1,6 @@
 module CopyTunerClient
   # Client version
-  VERSION = '0.17.1'.freeze
+  VERSION = '0.18.0'.freeze
 
   # API version being used to communicate with the server
   API_VERSION = '2.0'.freeze