diff --git a/api.py b/api.py
index 3b5a7e6..e6aeff1 100644
--- a/api.py
+++ b/api.py
@@ -77,9 +77,9 @@ def Subscribe(google_user, client, args):
     'events': models.Subscription.FindOrCreate(subject, client, messages),
   }
   for key in keys:
-    message = models.Subject.GetKey(key)
+    message = subject.GetKey(key)
     if message:
-      ret['events'].append(message)
+      ret['events'].append(message.ToEvent())
   return ret
 
 
diff --git a/static/test.js b/static/test.js
index ec40aa3..49d11a9 100644
--- a/static/test.js
+++ b/static/test.js
@@ -199,6 +199,38 @@ asyncTest('subscribe/unsubscribe Promise', function() {
   });
 });
 
+asyncTest('Duplicate message suppression', function() {
+  expect(3);
+
+  var subject = randstring();
+  var key = randstring();
+  var message1 = randstring();
+  var message2 = randstring();
+
+  var callbacks = {
+    'onMessage': function (msg) {
+      equal(msg['subject'], subject, 'subject matches');
+      equal(msg['key'], key, 'key matches');
+      equal(msg['message'], message1, 'message matches');
+      cosmo.shutdown();
+      start();
+    },
+  };
+
+  var cosmo = new Cosmopolite(callbacks, null, randstring());
+  // Break cosmo's UUID generator so that it generates duplicate values.
+  cosmo.uuid_ = function() {
+    return '4';
+    // chosen by fair dice roll.
+    // guaranteed to be random.
+  };
+  cosmo.sendMessage(subject, message1, key).then(function() {
+    cosmo.sendMessage(subject, message2, key).then(function() {
+      cosmo.subscribe(subject, 0, [key]);
+    });
+  });
+});
+
 
 module('dev_appserver only');