diff --git a/lib/raabro.rb b/lib/raabro.rb
index af6ebd5..da90e14 100644
--- a/lib/raabro.rb
+++ b/lib/raabro.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'stringio'
+
 module Raabro
 
   VERSION = '1.5.0'