diff --git a/main/main.cpp b/main/main.cpp
index 4828660..fa19f10 100644
--- a/main/main.cpp
+++ b/main/main.cpp
@@ -1,5 +1,9 @@
 constexpr const char * const TAG = "BOBBY";
 
+#ifndef OTA_USERNAME
+#error No OTA username!
+#endif
+
 // system includes
 #include <cstdio>