diff --git a/app/serializers/asciicast_serializer.rb b/app/serializers/asciicast_serializer.rb
index f448ae1..34de05e 100644
--- a/app/serializers/asciicast_serializer.rb
+++ b/app/serializers/asciicast_serializer.rb
@@ -11,7 +11,12 @@ class AsciicastSerializer < ActiveModel::Serializer
     if v0_url?
       object.stdout_frames_url
     else
-      asciicast_path(object, format: :json)
+      url = object.data.url
+      if url.starts_with?("/")
+        asciicast_path(object, format: :json) # download URL for local carrierwave store
+      else
+        url # direct signed S3 URL (because XHR CORS redirect doesn't work under Safari)
+      end
     end
   end