diff --git a/slskd_api/apis/application.py b/slskd_api/apis/application.py
index 7954859..db3e323 100644
--- a/slskd_api/apis/application.py
+++ b/slskd_api/apis/application.py
@@ -14,24 +14,26 @@ def state(self) -> dict:
         return response.json()
     
 
-# Getting Error 'Unauthorized' even with admin API-Key:
-    # def stop(self):
-    #     """
-    #     Stops the application.
-    #     """
-    #     url = self.api_url + '/application'
-    #     response = requests.delete(url, headers=self.header)
-    #     return response.ok
+    def stop(self) -> bool:
+        """
+        Stops the application. Only works with token (usr/pwd login). 'Unauthorized' with API-Key.
+        
+        :return: True if successful.
+        """
+        url = self.api_url + '/application'
+        response = requests.delete(url, headers=self.header)
+        return response.ok
     
 
-# Getting Error 'Unauthorized' even with admin API-Key:
-    # def restart(self):
-    #     """
-    #     Restarts the application.
-    #     """
-    #     url = self.api_url + '/application'
-    #     response = requests.put(url, headers=self.header)
-    #     return response.json()
+    def restart(self) -> bool:
+        """
+        Restarts the application. Only works with token (usr/pwd login). 'Unauthorized' with API-Key.
+        
+        :return: True if successful.
+        """
+        url = self.api_url + '/application'
+        response = requests.put(url, headers=self.header)
+        return response.ok
     
 
     def version(self) -> str:
diff --git a/slskd_api/apis/options.py b/slskd_api/apis/options.py
index 622f480..8d3ed3c 100644
--- a/slskd_api/apis/options.py
+++ b/slskd_api/apis/options.py
@@ -23,7 +23,7 @@ def get_startup(self) -> dict:
         return response.json()
 
   
-# Getting error 'Unauthorized':
+# Getting error 'Unauthorized'(API-Key) or 'Forbidden' (token):
     # def get_debug(self) -> dict:
     #     """
     #     Gets the debug view of the current application options.
diff --git a/slskd_api/client.py b/slskd_api/client.py
index 8596f38..94d4aaa 100644
--- a/slskd_api/client.py
+++ b/slskd_api/client.py
@@ -10,6 +10,7 @@ class SlskdClient:
     """
     The main class that allows access to the different APIs of a slskd instance.
     An API-Key with appropriate permissions (`readwrite` for most use cases) must be set in slskd config file.
+    Alternatively, provide your username and password.
     Usage::
         slskd = slskd_api.SlskdClient(host, api_key, url_base)
         app_status = slskd.application.state()
@@ -17,14 +18,23 @@ class SlskdClient:
 
     def __init__(self,
                  host: str,
-                 api_key: str,
-                 url_base: str = '/'
+                 api_key: str = None,
+                 url_base: str = '/',
+                 username: str = None,
+                 password: str = None,
     ):
         api_url = reduce(urljoin, [host, f'{url_base}/', f'api/{API_VERSION}'])
-        header = {
-            'accept': '*/*',
-            'X-API-Key': api_key
-        }
+     
+        header = {'accept': '*/*'}
+
+        if api_key:
+            header['X-API-Key'] = api_key
+        elif username and password:
+            header['Authorization'] = 'Bearer ' + \
+                            SessionApi(api_url, header).login(username, password)['token']
+        else:
+            raise ValueError('Please provide an API-Key or a valid username/password pair.')
+        
         base_args = (api_url, header)
         
         self.application = ApplicationApi(*base_args)