use os.environ.get

backend/settings.py

@@ -25,7 +25,7 @@ BASE_DIR = Path(__file__).resolve().parent.parent
 # See https://docs.djangoproject.com/en/5.2/howto/deployment/checklist/
 
 # SECURITY WARNING: keep the secret key used in production secret!
-SECRET_KEY = os.environ["SECRET_KEY"]
+SECRET_KEY = os.environ.get("SECRET_KEY", "local-dev-secret")
 
 # SECURITY WARNING: don't run with debug turned on in production!
 DEBUG = os.environ.get("DEBUG", "True") == "True"