diff --git a/app/config.py b/app/config.py
index 048dbca2..7177dbce 100644
--- a/app/config.py
+++ b/app/config.py
@@ -62,6 +62,12 @@ except Exception:
 # maximum number of directory a premium user can create
 MAX_NB_DIRECTORY = 50
 
+# transactional email sender
+SENDER = os.environ.get("SENDER")
+
+# the directory to store bounce emails
+SENDER_DIR = os.environ.get("SENDER_DIR")
+
 ENFORCE_SPF = "ENFORCE_SPF" in os.environ
 
 # allow to override postfix server locally
diff --git a/example.env b/example.env
index 53d38731..ca5c4c19 100644
--- a/example.env
+++ b/example.env
@@ -33,6 +33,11 @@ ALIAS_DOMAINS=["domain1.com", "domain2.com"]
 # transactional email is sent from this email address
 SUPPORT_EMAIL=support@sl.local
 SUPPORT_NAME=Son from SimpleLogin
+# in case sender is different than SUPPORT_EMAIL
+SENDER=sender@sl.local
+
+# all emails sent to sender are stored in this folder
+SENDER_DIR=/tmp
 
 # to receive general stats.
 # ADMIN_EMAIL=admin@sl.local