diff --git a/lib/typelizer/generator.rb b/lib/typelizer/generator.rb
index 9ac4224..2ecc677 100644
--- a/lib/typelizer/generator.rb
+++ b/lib/typelizer/generator.rb
@@ -16,14 +16,18 @@ def initialize(config = Typelizer::Config)
     def call(force: false)
       return unless Typelizer.enabled?
 
-      read_serializers
-
-      interfaces = target_serializers.map(&:typelizer_interface).reject(&:empty?)
       writer.call(interfaces, force: force)
 
       interfaces
     end
 
+    def interfaces
+      @interfaces ||= begin
+        read_serializers
+        target_serializers.map(&:typelizer_interface).reject(&:empty?)
+      end
+    end
+
     private
 
     def target_serializers