diff --git a/userapi/api/api.go b/userapi/api/api.go
index a80adf2d8..cf0f05633 100644
--- a/userapi/api/api.go
+++ b/userapi/api/api.go
@@ -36,7 +36,7 @@ type UserInternalAPI interface {
 type InputAccountDataRequest struct {
 	UserID      string          // required: the user to set account data for
 	RoomID      string          // optional: the room to associate the account data with
-	DataType    string          // optional: the data type of the data
+	DataType    string          // required: the data type of the data
 	AccountData json.RawMessage // required: the message content
 }