diff --git a/lib/omniauth/strategies/launch_pass.rb b/lib/omniauth/strategies/launch_pass.rb
index 78a6f88..31bec0c 100644
--- a/lib/omniauth/strategies/launch_pass.rb
+++ b/lib/omniauth/strategies/launch_pass.rb
@@ -20,6 +20,10 @@ class LaunchPass < OmniAuth::Strategies::OAuth2
         raw_info["user"]
       end
 
+      def callback_url
+        full_host + script_name + callback_path
+      end
+
       def setup_phase
         request.env['omniauth.strategy'].options[:authorize_params][:signing_up] =  request.params["signing_up"]
       end