diff --git a/lib/networking.js b/lib/networking.js
index 0d728ae..0217d12 100644
--- a/lib/networking.js
+++ b/lib/networking.js
@@ -91,6 +91,8 @@ exp.get_from_options = function(rid, url, options, callback) {
         break;
       case 404:
       case 204:
+      case 500:
+      case 503:
         // we don't want to cache this
         body = null;
         break;
@@ -107,6 +109,11 @@ exp.get_from_options = function(rid, url, options, callback) {
         break;
     }
 
+    if (body && !body.length) {
+      // empty response
+      body = null;
+    }
+
     callback(body, response, error);
   });
 };