diff --git a/README.md b/README.md
index fccf08f..c5dd55b 100644
--- a/README.md
+++ b/README.md
@@ -2,13 +2,14 @@
 
 ## Prerequisite
 
-`NAMESILO_API` in environment variable
+`NAMESILO_API` in environment variable or in `settings.conf`
 
 `settings.conf` in the same directory
 
 [default]
 domain=example.com
 subdomain=dynamic
+namesilo_api=SECRET_KEY
 
 ### Python3 library
 
diff --git a/update.py b/update.py
index 960daf3..7cfa486 100644
--- a/update.py
+++ b/update.py
@@ -62,15 +62,17 @@ def update_namesilo_data(key, domain, rrid, subdomain, new_value):
 
 
 def main():
-    api_key = os.environ['NAMESILO_API']
-    if not api_key:
-        print('NAMESILO_API in env is not found.')
-        sys.exit()
-    print('KEY: {}...'.format(api_key[:3]))
     config = configparser.ConfigParser()
     config.read('settings.conf')
     domain = config['default']['domain']
     subdomain = config['default']['subdomain']
+    api_key = os.environ.get('NAMESILO_API', None)
+    if not api_key:
+        if 'namesilo_api' not in config['default']:
+            print('NAMESILO_API not found.')
+            sys.exit()
+        api_key = config['default']['namesilo_api']
+    print('KEY: {}...'.format(api_key[:3]))
     target = '{}.{}'.format(subdomain, domain)
     print('TARGET: {}'.format(target))
     public_ip = get_public_ip()