diff --git a/models/Received.php b/models/Received.php
index 7c0f68d..57b7f44 100644
--- a/models/Received.php
+++ b/models/Received.php
@@ -16,6 +16,9 @@ namespace models;
      */
     class Received extends StandardModel
     {
+        const STATUS_UNREAD = 'unread';
+        const STATUS_READ = 'read';
+
         /**
          * Return a list of unread received for a user.
          *
diff --git a/models/Webhook.php b/models/Webhook.php
index 16b2f1c..2f4fa76 100644
--- a/models/Webhook.php
+++ b/models/Webhook.php
@@ -13,6 +13,10 @@ namespace models;
 
     class Webhook extends StandardModel
     {
+        const TYPE_SEND = 'send_sms';
+        const TYPE_RECEIVE = 'receive_sms';
+
+
         /**
          * Find all webhooks for a user and for a type of webhook.
          *