diff --git a/mopidy/backends/spotify/session_manager.py b/mopidy/backends/spotify/session_manager.py
index 8f520896..125b6ada 100644
--- a/mopidy/backends/spotify/session_manager.py
+++ b/mopidy/backends/spotify/session_manager.py
@@ -33,9 +33,17 @@ class SpotifySessionManager(process.BaseThread, PyspotifySessionManager):
         self.cache_location = config['spotify']['cache_dir']
         self.settings_location = config['spotify']['cache_dir']
 
+        full_proxy = ''
+        if config['proxy']['hostname']:
+            full_proxy = config['proxy']['hostname']
+            if config['proxy']['port']:
+                full_proxy += ':' + str(config['proxy']['port'])
+            if config['proxy']['scheme']:
+                full_proxy = config['proxy']['scheme'] + "://" + full_proxy
+
         PyspotifySessionManager.__init__(
             self, config['spotify']['username'], config['spotify']['password'],
-            proxy=config['proxy']['hostname'],
+            proxy=full_proxy,
             proxy_username=config['proxy']['username'],
             proxy_password=config['proxy']['password'])
 
diff --git a/mopidy/config/__init__.py b/mopidy/config/__init__.py
index e9ae7d86..dfdae6a7 100644
--- a/mopidy/config/__init__.py
+++ b/mopidy/config/__init__.py
@@ -26,7 +26,10 @@ _audio_schema['mixer_track'] = String(optional=True)
 _audio_schema['output'] = String()
 
 _proxy_schema = ConfigSchema('proxy')
+_proxy_schema['scheme'] = String(optional=True,
+                                 choices=['http', 'https', 'socks4', 'socks5'])
 _proxy_schema['hostname'] = Hostname(optional=True)
+_proxy_schema['port'] = Port(optional=True)
 _proxy_schema['username'] = String(optional=True)
 _proxy_schema['password'] = Secret(optional=True)
 
diff --git a/mopidy/config/convert.py b/mopidy/config/convert.py
index 6cb20fcd..3c3edb85 100644
--- a/mopidy/config/convert.py
+++ b/mopidy/config/convert.py
@@ -39,6 +39,7 @@ def convert(settings):
     helper('audio/output', 'OUTPUT')
 
     helper('proxy/hostname', 'SPOTIFY_PROXY_HOST')
+    helper('proxy/port', 'SPOTIFY_PROXY_PORT')
     helper('proxy/username', 'SPOTIFY_PROXY_USERNAME')
     helper('proxy/password', 'SPOTIFY_PROXY_PASSWORD')
 
diff --git a/mopidy/config/default.conf b/mopidy/config/default.conf
index b525ef47..3899c2c5 100644
--- a/mopidy/config/default.conf
+++ b/mopidy/config/default.conf
@@ -13,6 +13,8 @@ mixer_track =
 output = autoaudiosink
 
 [proxy]
+scheme =
 hostname =
+port = 
 username =
 password =
diff --git a/mopidy/config/types.py b/mopidy/config/types.py
index ec0be1de..29651940 100644
--- a/mopidy/config/types.py
+++ b/mopidy/config/types.py
@@ -71,9 +71,9 @@ class String(ConfigValue):
     def deserialize(self, value):
         value = decode(value).strip()
         validators.validate_required(value, self._required)
-        validators.validate_choice(value, self._choices)
         if not value:
             return None
+        validators.validate_choice(value, self._choices)
         return value
 
     def serialize(self, value, display=False):
@@ -111,12 +111,16 @@ class Secret(ConfigValue):
 class Integer(ConfigValue):
     """Integer value."""
 
-    def __init__(self, minimum=None, maximum=None, choices=None):
+    def __init__(self, minimum=None, maximum=None, choices=None, optional=False):
+        self._required = not optional
         self._minimum = minimum
         self._maximum = maximum
         self._choices = choices
 
     def deserialize(self, value):
+        validators.validate_required(value, self._required)
+        if not value:
+            return None
         value = int(value)
         validators.validate_choice(value, self._choices)
         validators.validate_minimum(value, self._minimum)
@@ -222,9 +226,9 @@ class Port(Integer):
     allocate a port for us.
     """
     # TODO: consider probing if port is free or not?
-    def __init__(self, choices=None):
+    def __init__(self, choices=None, optional=False):
         super(Port, self).__init__(
-            minimum=0, maximum=2 ** 16 - 1, choices=choices)
+            minimum=0, maximum=2 ** 16 - 1, choices=choices, optional=optional)
 
 
 class Path(ConfigValue):
diff --git a/tests/config/types_test.py b/tests/config/types_test.py
index 88c8f067..74e9672d 100644
--- a/tests/config/types_test.py
+++ b/tests/config/types_test.py
@@ -98,6 +98,11 @@ class StringTest(unittest.TestCase):
         self.assertIsInstance(result, bytes)
         self.assertEqual(b'', result)
 
+    def test_deserialize_enforces_choices_optional(self):
+        value = types.String(optional=True, choices=['foo', 'bar', 'baz'])
+        self.assertEqual(None, value.deserialize(b''))
+        self.assertRaises(ValueError, value.deserialize, b'foobar')
+
 
 class SecretTest(unittest.TestCase):
     def test_deserialize_passes_through(self):
@@ -163,6 +168,10 @@ class IntegerTest(unittest.TestCase):
         self.assertEqual(5, value.deserialize('5'))
         self.assertRaises(ValueError, value.deserialize, '15')
 
+    def test_deserialize_respects_optional(self):
+        value = types.Integer(optional=True)
+        self.assertEqual(None, value.deserialize(''))
+
 
 class BooleanTest(unittest.TestCase):
     def test_deserialize_conversion_success(self):