diff --git a/api.py b/api.py
index 159737a..9fd99e4 100644
--- a/api.py
+++ b/api.py
@@ -50,8 +50,9 @@ def CreateChannel(google_user, client, args):
 def SendMessage(google_user, client, args):
   subject = args['subject']
   message = args['message']
+  key = args.get('key', None)
 
-  models.Subject.FindOrCreate(subject).SendMessage(message, client.parent_key())
+  models.Subject.FindOrCreate(subject).SendMessage(message, client.parent_key(), key)
 
   return {}
 
@@ -90,10 +91,16 @@ def SetValue(google_user, client, args):
 def Subscribe(google_user, client, args):
   subject = models.Subject.FindOrCreate(args['subject'])
   messages = args.get('messages', 0)
+  keys = args.get('keys', [])
 
-  return {
+  ret = {
     'events': models.Subscription.FindOrCreate(subject, client, messages),
   }
+  for key in keys:
+    message = models.Subject.GetKey(key)
+    if message:
+      ret['events'].append(message)
+  return ret
 
 
 def Unsubscribe(google_user, client, args):
diff --git a/lib/models.py b/lib/models.py
index 6ad532a..4d5a30d 100644
--- a/lib/models.py
+++ b/lib/models.py
@@ -27,6 +27,7 @@ import utils
 # ↳ StateEntry
 #
 # Subject
+# ↳ Message
 # ↳ Subscription (⤴︎ Client)
 
 
@@ -132,7 +133,7 @@ class Subject(db.Model):
     return cls(key_name=name).put()
 
   @db.transactional()
-  def RecentMessages(self, num_messages):
+  def GetRecentMessages(self, num_messages):
     query = (
         Message.all()
         .ancestor(self)
@@ -142,8 +143,20 @@ class Subject(db.Model):
     return reversed(query.fetch(limit=num_messages))
 
   @db.transactional()
-  def SendMessage(self, message, sender):
-    obj = Message(parent=self, message=message, sender=sender)
+  def GetKey(self, key):
+    messages = (
+        Message.all()
+        .ancestor(self)
+        .filter('key_ =', key)
+        .order('-created')
+        .fetch(1))
+    if messages:
+      return messages[0]
+    return None
+
+  @db.transactional()
+  def SendMessage(self, message, sender, key=None):
+    obj = Message(parent=self, message=message, sender=sender, key_=key)
     obj.put()
 
     event = obj.ToEvent()
@@ -169,7 +182,7 @@ class Subscription(db.Model):
       cls(parent=subject, client=client).put()
     if messages == 0:
       return []
-    return [m.ToEvent() for m in subject.RecentMessages(messages)]
+    return [m.ToEvent() for m in subject.GetRecentMessages(messages)]
 
   @classmethod
   @db.transactional()
@@ -188,9 +201,11 @@ class Message(db.Model):
   created = db.DateTimeProperty(required=True, auto_now_add=True)
   message = db.TextProperty(required=True)
   sender = db.ReferenceProperty(required=True, reference_class=Profile)
+  # key and key_name are reserved
+  key_ = db.StringProperty()
 
   def ToEvent(self):
-    return {
+    ret = {
       'event_type':   'message',
       'id':           self.key().id(),
       'sender':       str(Message.sender.get_value_for_datastore(self)),
@@ -198,3 +213,6 @@ class Message(db.Model):
       'created':      self.created,
       'message':      self.message,
     }
+    if self.key_:
+      ret['key'] = self.key_
+    return ret
diff --git a/static/cosmopolite.js b/static/cosmopolite.js
index adf5e0f..5b8326e 100644
--- a/static/cosmopolite.js
+++ b/static/cosmopolite.js
@@ -88,11 +88,15 @@ cosmopolite.Client.prototype.unsubscribe = function(subject) {
   });
 };
 
-cosmopolite.Client.prototype.sendMessage = function(subject, message) {
-  this.sendRPC_('sendMessage', {
+cosmopolite.Client.prototype.sendMessage = function(subject, message, key) {
+  args = {
     'subject': subject,
     'message': message,
-  });
+  };
+  if (key) {
+    args['key'] = key;
+  }
+  this.sendRPC_('sendMessage', args);
 };
 
 cosmopolite.Client.prototype.getMessages = function(subject) {
diff --git a/static/debug.html b/static/debug.html
index 3c2e5c5..0454db4 100644
--- a/static/debug.html
+++ b/static/debug.html
@@ -11,39 +11,49 @@ a {
     <div>Google user: <span id="google_user"></span></div>
 
     <div>
-      <div>
-        Key:
-        <select id="keys"></select>
-        <input type="button" id="set" value="Set">
-        <input type="button" id="add" value="Add">
-      </div>
-      <div>
-        Last set:
-        <span id="last_set"></span>
-      </div>
-      <div>
-        <input type="checkbox" id="public"> Public
-      </div>
-      <div>
-        <textarea id="value" rows="10" cols="40"></textarea>
-      </div>
+      Key:
+      <select id="keys"></select>
+      <input type="button" id="set" value="Set">
+      <input type="button" id="add" value="Add">
     </div>
-    <hr>
     <div>
-      <div>
-        Subject:
-        <input type="text" id="subject">
-        <input type="button" id="subscribe" value="Subscribe">
-      </div>
-      <div>
-        <select id="subscriptions"></select>
-        <input type="button" id="unsubscribe" value="Unsubscribe">
-      </div>
-      <div>
-        <input type="text" id="message">
-        <input type="button" id="send" value="Send">
-      </div>
-      <div id="messages"></div>
+      Last set:
+      <span id="last_set"></span>
+    </div>
+    <div>
+      <input type="checkbox" id="public"> Public
+    </div>
+    <div>
+      <textarea id="value" rows="10" cols="40"></textarea>
+    </div>
+
+    <hr>
+
+    <div>
+      Subject: <input type="text" id="subject">
+      <input type="button" id="subscribe" value="Subscribe">
+    </div>
+    <div>
+      <select id="subscriptions"></select>
+      <input type="button" id="unsubscribe" value="Unsubscribe">
+    </div>
+
+    <hr>
+
+    <div>
+      Message: <input type="text" id="message">
+    </div>
+    <div>
+      Key: <input type="text" id="key">
+    </div>
+    <div>
+      <input type="button" id="send" value="Send">
+    </div>
+
+    <hr>
+
+    <div id="messages"></div>
+
     <script>
 var keys = document.getElementById('keys');
 var value = document.getElementById('value');
@@ -52,8 +62,11 @@ var is_public = document.getElementById('public');
 
 var subject = document.getElementById('subject');
 var subscriptions = document.getElementById('subscriptions');
-var messages = document.getElementById('messages');
+
 var message = document.getElementById('message');
+var key = document.getElementById('key');
+
+var messages = document.getElementById('messages');
 
 var selectKey = function(new_key) {
   keys.value = new_key;
@@ -150,7 +163,7 @@ window.addEventListener('load', function() {
   });
 
   document.getElementById('send').addEventListener('click', function() {
-    debug.sendMessage(subscriptions.value, message.value);
+    debug.sendMessage(subscriptions.value, message.value, key.value);
   });
 
   document.getElementById('subscriptions').addEventListener('change', function() {