diff --git a/flask_sslify.py b/flask_sslify.py
index 8fa2846..b56975b 100644
--- a/flask_sslify.py
+++ b/flask_sslify.py
@@ -8,7 +8,7 @@ YEAR_IN_SECS = 31536000
 class SSLify(object):
     """Secures your Flask App."""
 
-    def __init__(self, app, age=YEAR_IN_SECS, subdomains=False, permanent=False, skips=None):
+    def __init__(self, app=None, age=YEAR_IN_SECS, subdomains=False, permanent=False, skips=None):
         if app is not None:
             self.init_app(app)
             self.app = app