diff --git a/src/user.js b/src/user.js
index 188c5a75d..62f972296 100644
--- a/src/user.js
+++ b/src/user.js
@@ -88,6 +88,8 @@ function validateUsername(username) {
 
     if (RESERVED_USERNAMES.indexOf(username) !== -1) return new UserError(UserError.BAD_USERNAME, 'Username is reserved');
 
+    if (username.indexOf('-app') !== -1) return UserError(UserError.BAD_USERNAME, 'Username pattern is reserved for apps');
+
     return null;
 }