diff --git a/api/html/openapi.json b/api/html/openapi.json
index 6af9f42..d04650a 100644
--- a/api/html/openapi.json
+++ b/api/html/openapi.json
@@ -174,7 +174,9 @@
           },
           "workingHours": {
             "description": "Arbeitszeit des Tages",
-            "type": "integer"
+            "type": "string",
+            "pattern": "[0-5]\\d:[0-5]\\d:[0-5]\\d",
+            "example": "08:01:00"
           }
         }
       },