diff --git a/note_kfet/settings/__init__.py b/note_kfet/settings/__init__.py
index a2e28372..6d871599 100644
--- a/note_kfet/settings/__init__.py
+++ b/note_kfet/settings/__init__.py
@@ -33,14 +33,42 @@ if app_stage == 'prod':
 
     DATABASES["default"]["PASSWORD"] = os.environ.get('DJANGO_DB_PASSWORD', 'CHANGE_ME_IN_ENV_SETTINGS')
     SECRET_KEY = os.environ.get('DJANGO_SECRET_KEY', 'CHANGE_ME_IN_ENV_SETTINGS')
-    ALLOWED_HOSTS.append(os.environ.get('ALLOWED_HOSTS', 'localhost'))
+    ALLOWED_HOSTS = [os.environ.get('ALLOWED_HOSTS', 'localhost')]
 else:
     from .development import *
 
 try:
+    #in secrets.py defines everything you want
     from .secrets import *
 except ImportError:
     pass
 
-# env variables set at the of in /env/bin/activate
-# don't forget to unset in deactivate !
+if "cas" in INSTALLED_APPS:
+    MIDDLEWARE += ['cas.middleware.CASMiddleware']
+    # CAS Settings
+    CAS_AUTO_CREATE_USER = False
+    CAS_LOGO_URL = "/static/img/Saperlistpopette.png"
+    CAS_FAVICON_URL = "/static/favicon/favicon-32x32.png"
+    CAS_SHOW_SERVICE_MESSAGES = True
+    CAS_SHOW_POWERED = False
+    CAS_REDIRECT_TO_LOGIN_AFTER_LOGOUT = False
+    CAS_INFO_MESSAGES = {
+        "cas_explained": {
+            "message": _(
+                u"The Central Authentication Service grants you access to most of our websites by "
+                u"authenticating only once, so you don't need to type your credentials again unless "
+                u"your session expires or you logout."
+            ),
+           "discardable": True,
+            "type": "info",  # one of info, success, info, warning, danger
+       },
+    }
+
+    CAS_INFO_MESSAGES_ORDER = [
+        'cas_explained',
+    ]
+    AUTHENTICATION_BACKENDS += ('cas.backends.CASBackend',)
+    
+if "debug_toolbar" in INSTALLED_APPS:
+    MIDDLEWARE.insert(1,"debug_toolbar.middleware.DebugToolbarMiddleware")
+    INTERNAL_IPS = [ '127.0.0.1']
diff --git a/note_kfet/settings/base.py b/note_kfet/settings/base.py
index fead0e44..a1dbb929 100644
--- a/note_kfet/settings/base.py
+++ b/note_kfet/settings/base.py
@@ -54,9 +54,6 @@ INSTALLED_APPS = [
     # Autocomplete
     'dal',
     'dal_select2',
-    # CAS
-    'cas_server',
-    'cas',
 
     # Note apps
     'activity',
@@ -79,7 +76,6 @@ MIDDLEWARE = [
     'django.middleware.locale.LocaleMiddleware',
     'django.contrib.sites.middleware.CurrentSiteMiddleware',
     'note_kfet.middlewares.TurbolinksMiddleware',
-    'cas.middleware.CASMiddleware',
 ]
 
 ROOT_URLCONF = 'note_kfet.urls'
@@ -133,7 +129,6 @@ PASSWORD_HASHERS = [
 AUTHENTICATION_BACKENDS = (
     'django.contrib.auth.backends.ModelBackend',  # this is default
     'guardian.backends.ObjectPermissionBackend',
-    'cas.backends.CASBackend',
 )
 
 REST_FRAMEWORK = {
@@ -200,26 +195,3 @@ MEDIA_URL = '/media/'
 # Profile Picture Settings
 PIC_WIDTH = 200
 PIC_RATIO = 1
-
-# CAS Settings
-CAS_AUTO_CREATE_USER = False
-CAS_LOGO_URL = "/static/img/Saperlistpopette.png"
-CAS_FAVICON_URL = "/static/favicon/favicon-32x32.png"
-CAS_SHOW_SERVICE_MESSAGES = True
-CAS_SHOW_POWERED = False
-CAS_REDIRECT_TO_LOGIN_AFTER_LOGOUT = False
-CAS_INFO_MESSAGES = {
-    "cas_explained": {
-        "message": _(
-            u"The Central Authentication Service grants you access to most of our websites by "
-            u"authenticating only once, so you don't need to type your credentials again unless "
-            u"your session expires or you logout."
-        ),
-        "discardable": True,
-        "type": "info",  # one of info, success, info, warning, danger
-    },
-}
-
-CAS_INFO_MESSAGES_ORDER = [
-    'cas_explained',
-]
diff --git a/note_kfet/settings/secrets_example.py b/note_kfet/settings/secrets_example.py
new file mode 100644
index 00000000..70d17ad4
--- /dev/null
+++ b/note_kfet/settings/secrets_example.py
@@ -0,0 +1,9 @@
+# Copyright (C) 2018-2020 by BDE ENS Paris-Saclay
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# CAS
+OPTIONAL_APPS = [
+#    'cas_server',
+#    'cas',
+#    'debug_toolbar'
+]
diff --git a/note_kfet/urls.py b/note_kfet/urls.py
index 56251955..896c0655 100644
--- a/note_kfet/urls.py
+++ b/note_kfet/urls.py
@@ -1,7 +1,6 @@
 # Copyright (C) 2018-2020 by BDE ENS Paris-Saclay
 # SPDX-License-Identifier: GPL-3.0-or-later
 
-from cas import views as cas_views
 from django.conf import settings
 from django.conf.urls.static import static
 from django.contrib import admin
@@ -15,25 +14,35 @@ urlpatterns = [
     # Include project routers
     path('note/', include('note.urls')),
 
-    # Include CAS Client routers
-    path('accounts/login/', cas_views.login, name='login'),
-    path('accounts/logout/', cas_views.logout, name='logout'),
-
     # Include Django Contrib and Core routers
     path('i18n/', include('django.conf.urls.i18n')),
     path('accounts/', include('member.urls')),
     path('accounts/', include('django.contrib.auth.urls')),
     path('admin/doc/', include('django.contrib.admindocs.urls')),
     path('admin/', admin.site.urls),
-
-    # Include CAS Server routers
-    path('cas/', include('cas_server.urls', namespace="cas_server")),
-
-    # Include Django REST API
-    path('api/', include('api.urls')),
-
     path('logs/', include('logs.urls')),
+    path('api/', include('api.urls')),  
 ]
 
 urlpatterns += static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)
 urlpatterns += static(settings.STATIC_URL, document_root=settings.STATIC_ROOT)
+
+
+if "cas_server" in settings.INSTALLED_APPS:
+    urlpatterns += [
+        # Include CAS Server routers
+        path('cas/', include('cas_server.urls', namespace="cas_server")),
+    ]
+if "cas" in settings.INSTALLED_APPS:
+    from cas import views as cas_views
+    urlpatterns += [
+        # Include CAS Client routers
+        path('accounts/login/', cas_views.login, name='login'),
+        path('accounts/logout/', cas_views.logout, name='logout'),
+       
+    ]
+if "debug_toolbar" in settings.INSTALLED_APPS:
+    import debug_toolbar
+    urlpatterns = [
+        path('__debug__/', include(debug_toolbar.urls)),
+    ] + urlpatterns