diff --git a/src/main/java/at/aau/serg/autoguard/example/models/Customer.java b/src/main/java/at/aau/serg/autoguard/example/models/Customer.java
index 5e8f2f8..1572b98 100644
--- a/src/main/java/at/aau/serg/autoguard/example/models/Customer.java
+++ b/src/main/java/at/aau/serg/autoguard/example/models/Customer.java
@@ -16,6 +16,7 @@ public class Customer {
 
     private String name;
 
+    @NotNull
     private String email;
 
 }