diff --git a/config.example.toml b/config.example.toml
index c969ef02a08f5091bd7f64e80f9218898313821b..9ac191302cd20ffe55f9cf4629719e7b60d6370b 100644
--- a/config.example.toml
+++ b/config.example.toml
@@ -4,6 +4,7 @@ MAX_CONTENT_LENGTH = 10 # in GB
 
 ENABLED_LOCALISATIONS = [ "de", "en" ]
 DEFAULT_LANGUAGE = "de"
+MAIL_DOMAIN = "ptb.de"
 
 [ CONTACT ]
 ORG = "Fun Inc."
diff --git a/routes.py b/routes.py
index 36d65949bd0d79326609d69ef4c9e070ec7809f7..442c5d2a7209aad733c07402453a00a9c0724f12 100644
--- a/routes.py
+++ b/routes.py
@@ -18,8 +18,8 @@ def upload(language: str):
     ]
 
     if form.is_submitted():
-        if form.email.data:
-            form.email.data += "@ptb.de"
+        if not form.email.data.endswith(current_app.config["MAIL_DOMAIN"]):
+            form.email.data += current_app.config["MAIL_DOMAIN"]
 
         if form.validate():