diff --git a/app/controllers/robots_controller.rb b/app/controllers/robots_controller.rb
index fda10c506..1c13acaeb 100644
--- a/app/controllers/robots_controller.rb
+++ b/app/controllers/robots_controller.rb
@@ -2,5 +2,6 @@ class RobotsController < ApplicationController
   respond_to :text
 
   def index
+    expires_in 1.hour, public: true unless response.cache_control.present?
   end
 end