diff --git a/server/core/hep_client.py b/server/core/hep_client.py
index f4bbc60d..91c2396b 100644
--- a/server/core/hep_client.py
+++ b/server/core/hep_client.py
@@ -43,7 +43,7 @@ class HepClient:
 
     def _call(self, url, method='get', data=None, additional_headers=None):
 
-        request_url = '{}{}'.format(self.URL, url)
+        request_url = f'{self.URL}{url}'
 
         if additional_headers:
             headers = {**additional_headers, **self.HEADERS}
diff --git a/server/core/settings.py b/server/core/settings.py
index 51cafc6b..0914091b 100644
--- a/server/core/settings.py
+++ b/server/core/settings.py
@@ -379,9 +379,9 @@ TASKBASE_BASEURL = os.environ.get("TASKBASE_BASEURL")
 ALLOW_BETA_LOGIN = True
 
 # HEP
-HEP_URL = os.path.join("HEP_ADMIN_USER", "myskillbox")
-HEP_URL = os.path.join("HEP_ADMIN_PASSWORD", "dSgqCv7zhEMmSNrw")
-HEP_URL = os.path.join("GRAPHQL_QUERIES_DIR", "https://stage.hep-verlag.ch")
+HEP_ADMIN_USER = os.environ.get("HEP_ADMIN_USER")
+HEP_ADMIN_PASSWORD = os.environ.get("HEP_ADMIN_PASSWORD")
+HEP_URL = os.environ.get("HEP_URL")