diff --git a/specification/application_service_api.rst b/specification/application_service_api.rst
index 0429ec69..1f442748 100644
--- a/specification/application_service_api.rst
+++ b/specification/application_service_api.rst
@@ -233,7 +233,7 @@ including the AS token on a ``/register`` request, along with a login type of
   Content:
   {
     type: "m.login.application_service",
-    username: "<desired user localpart in AS namespace>"
+    user: "<desired user localpart in AS namespace>"
   }
 
 Application services which attempt to create users or aliases *outside* of