diff --git a/optimizely/decision_service.py b/optimizely/decision_service.py
index 3e424302..6b50f77b 100644
--- a/optimizely/decision_service.py
+++ b/optimizely/decision_service.py
@@ -1,4 +1,4 @@
-# Copyright 2017, Optimizely
+# Copyright 2017-2018, Optimizely
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
@@ -23,7 +23,6 @@
 Decision = namedtuple('Decision', 'experiment variation source')
 DECISION_SOURCE_EXPERIMENT = 'experiment'
 DECISION_SOURCE_ROLLOUT = 'rollout'
-RESERVED_BUCKETING_ID_ATTRIBUTE = '$opt_bucketing_id'
 
 
 class DecisionService(object):
@@ -48,7 +47,7 @@ def _get_bucketing_id(user_id, attributes):
     """
 
     attributes = attributes or {}
-    return attributes.get(RESERVED_BUCKETING_ID_ATTRIBUTE, user_id)
+    return attributes.get(enums.ControlAttributes.BUCKETING_ID, user_id)
 
   def get_forced_variation(self, experiment, user_id):
     """ Determine if a user is forced into a variation for the given experiment and return that variation.
diff --git a/optimizely/event_builder.py b/optimizely/event_builder.py
index 4f4be6f0..087dc1bf 100644
--- a/optimizely/event_builder.py
+++ b/optimizely/event_builder.py
@@ -17,6 +17,7 @@
 from abc import abstractproperty
 
 from . import version
+from .helpers import enums
 from .helpers import event_tag_utils
 
 
@@ -80,11 +81,20 @@ def _get_anonymize_ip(self):
     """ Get IP anonymization bool
 
     Returns:
-      bool 'anonymizeIP' value in the datafile.
+      Boolean representing whether IP anonymization is enabled or not.
     """
 
     return self.config.get_anonymize_ip_value()
 
+  def _get_bot_filtering(self):
+    """ Get bot filtering bool
+
+    Returns:
+      Boolean representing whether bot filtering is enabled or not.
+    """
+
+    return self.config.get_bot_filtering_value()
+
   @abstractmethod
   def _get_time(self):
     """ Get time in milliseconds to be added.
@@ -169,21 +179,29 @@ def _get_attributes(self, attributes):
 
     params = []
 
-    if not attributes:
-      return []
-
-    for attribute_key in attributes.keys():
-      attribute_value = attributes.get(attribute_key)
-      # Omit falsy attribute values
-      if attribute_value:
-        attribute = self.config.get_attribute(attribute_key)
-        if attribute:
-          params.append({
-            self.EventParams.EVENT_ID: attribute.id,
-            'key': attribute_key,
-            'type': self.EventParams.CUSTOM,
-            'value': attribute_value,
-          })
+    if isinstance(attributes, dict):
+      for attribute_key in attributes.keys():
+        attribute_value = attributes.get(attribute_key)
+        # Omit falsy attribute values
+        if attribute_value:
+          attribute_id = self.config.get_attribute_id(attribute_key)
+          if attribute_id:
+            params.append({
+              'entity_id': attribute_id,
+              'key': attribute_key,
+              'type': self.EventParams.CUSTOM,
+              'value': attribute_value
+            })
+
+    # Append Bot Filtering Attribute
+    bot_filtering_value = self._get_bot_filtering()
+    if isinstance(bot_filtering_value, bool):
+      params.append({
+          'entity_id': enums.ControlAttributes.BOT_FILTERING,
+          'key': enums.ControlAttributes.BOT_FILTERING,
+          'type': self.EventParams.CUSTOM,
+          'value': bot_filtering_value
+      })
 
     return params
 
diff --git a/optimizely/helpers/enums.py b/optimizely/helpers/enums.py
index e0f0fd0c..a8ff454a 100644
--- a/optimizely/helpers/enums.py
+++ b/optimizely/helpers/enums.py
@@ -1,4 +1,4 @@
-# Copyright 2016-2017, Optimizely
+# Copyright 2016-2018, Optimizely
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
@@ -59,3 +59,9 @@ class NotificationTypes(object):
   """
   ACTIVATE = "ACTIVATE:experiment, user_id, attributes, variation, event"
   TRACK = "TRACK:event_key, user_id, attributes, event_tags, event"
+
+
+class ControlAttributes(object):
+  BOT_FILTERING = '$opt_bot_filtering'
+  BUCKETING_ID = '$opt_bucketing_id'
+  USER_AGENT = '$opt_user_agent'
diff --git a/optimizely/project_config.py b/optimizely/project_config.py
index a42cf85f..49ea28c1 100644
--- a/optimizely/project_config.py
+++ b/optimizely/project_config.py
@@ -25,6 +25,8 @@
 SUPPORTED_VERSIONS = [V2_CONFIG_VERSION]
 UNSUPPORTED_VERSIONS = [V1_CONFIG_VERSION]
 
+RESERVED_ATTRIBUTE_PREFIX = '$opt_'
+
 
 class ProjectConfig(object):
   """ Representation of the Optimizely project config. """
@@ -56,6 +58,7 @@ def __init__(self, datafile, logger, error_handler):
     self.feature_flags = config.get('featureFlags', [])
     self.rollouts = config.get('rollouts', [])
     self.anonymize_ip = config.get('anonymizeIP', False)
+    self.bot_filtering = config.get('botFiltering', None)
 
     # Utility maps for quick lookup
     self.group_id_map = self._generate_key_map(self.groups, 'id', entities.Group)
@@ -363,20 +366,28 @@ def get_event(self, event_key):
     self.error_handler.handle_error(exceptions.InvalidEventException(enums.Errors.INVALID_EVENT_KEY_ERROR))
     return None
 
-  def get_attribute(self, attribute_key):
-    """ Get attribute for the provided attribute key.
+  def get_attribute_id(self, attribute_key):
+    """ Get attribute ID for the provided attribute key.
 
     Args:
       attribute_key: Attribute key for which attribute is to be fetched.
 
     Returns:
-      Attribute corresponding to the provided attribute key.
+      Attribute ID corresponding to the provided attribute key.
     """
 
     attribute = self.attribute_key_map.get(attribute_key)
+    has_reserved_prefix = attribute_key.startswith(RESERVED_ATTRIBUTE_PREFIX)
 
     if attribute:
-      return attribute
+      if has_reserved_prefix:
+        self.logger.warning(('Attribute %s unexpectedly has reserved prefix %s; using attribute ID '
+                             'instead of reserved attribute name.' % (attribute_key, RESERVED_ATTRIBUTE_PREFIX)))
+
+      return attribute.id
+
+    if has_reserved_prefix:
+      return attribute_key
 
     self.logger.error('Attribute "%s" is not in datafile.' % attribute_key)
     self.error_handler.handle_error(exceptions.InvalidAttributeException(enums.Errors.INVALID_ATTRIBUTE_ERROR))
@@ -595,3 +606,12 @@ def get_anonymize_ip_value(self):
     """
 
     return self.anonymize_ip
+
+  def get_bot_filtering_value(self):
+    """ Gets the bot filtering value.
+
+      Returns:
+        A boolean value that indicates if bot filtering should be enabled.
+    """
+
+    return self.bot_filtering
diff --git a/tests/base.py b/tests/base.py
index 7af62c99..72b78c7a 100644
--- a/tests/base.py
+++ b/tests/base.py
@@ -145,6 +145,7 @@ def setUp(self):
       'accountId': '12001',
       'projectId': '111111',
       'version': '4',
+      'botFiltering': True,
       'events': [{
         'key': 'test_event',
         'experimentIds': ['111127'],
diff --git a/tests/test_config.py b/tests/test_config.py
index a22929d6..8bc6ee37 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -172,6 +172,7 @@ def test_init__with_v4_datafile(self):
       'revision': '42',
       'version': '4',
       'anonymizeIP': False,
+      'botFiltering': True,
       'events': [{
         'key': 'test_event',
         'experimentIds': ['111127'],
@@ -387,6 +388,7 @@ def test_init__with_v4_datafile(self):
     self.assertEqual(config_dict['revision'], project_config.revision)
     self.assertEqual(config_dict['experiments'], project_config.experiments)
     self.assertEqual(config_dict['events'], project_config.events)
+    self.assertEqual(config_dict['botFiltering'], project_config.bot_filtering)
 
     expected_group_id_map = {
       '19228': entities.Group(
@@ -679,6 +681,21 @@ def test_get_project_id(self):
 
     self.assertEqual(self.config_dict['projectId'], self.project_config.get_project_id())
 
+  def test_get_bot_filtering(self):
+    """ Test that bot filtering is retrieved correctly when using get_bot_filtering_value. """
+
+    # Assert bot filtering is None when not provided in data file
+    self.assertTrue('botFiltering' not in self.config_dict)
+    self.assertIsNone(self.project_config.get_bot_filtering_value())
+
+    # Assert bot filtering is retrieved as provided in the data file
+    opt_obj = optimizely.Optimizely(json.dumps(self.config_dict_with_features))
+    project_config = opt_obj.config
+    self.assertEqual(
+        self.config_dict_with_features['botFiltering'],
+        project_config.get_bot_filtering_value()
+    )
+
   def test_get_experiment_from_key__valid_key(self):
     """ Test that experiment is retrieved correctly for valid experiment key. """
 
@@ -787,16 +804,27 @@ def test_get_event__invalid_key(self):
 
     self.assertIsNone(self.project_config.get_event('invalid_key'))
 
-  def test_get_attribute__valid_key(self):
-    """ Test that attribute is retrieved correctly for valid attribute key. """
+  def test_get_attribute_id__valid_key(self):
+    """ Test that attribute ID is retrieved correctly for valid attribute key. """
 
-    self.assertEqual(entities.Attribute('111094', 'test_attribute'),
-                     self.project_config.get_attribute('test_attribute'))
+    self.assertEqual('111094',
+                     self.project_config.get_attribute_id('test_attribute'))
 
-  def test_get_attribute__invalid_key(self):
+  def test_get_attribute_id__invalid_key(self):
     """ Test that None is returned when provided attribute key is invalid. """
 
-    self.assertIsNone(self.project_config.get_attribute('invalid_key'))
+    self.assertIsNone(self.project_config.get_attribute_id('invalid_key'))
+
+  def test_get_attribute_id__reserved_key(self):
+    """ Test that Attribute Key is returned as ID when provided attribute key is reserved key. """
+    self.assertEqual('$opt_user_agent',
+                       self.project_config.get_attribute_id('$opt_user_agent'))
+
+  def test_get_attribute_id__unknown_key_with_opt_prefix(self):
+    """ Test that Attribute Key is returned as ID when provided attribute key is not
+    present in the datafile but has $opt prefix. """
+    self.assertEqual('$opt_interesting',
+                     self.project_config.get_attribute_id('$opt_interesting'))
 
   def test_get_group__valid_id(self):
     """ Test that group is retrieved correctly for valid group ID. """
@@ -1074,6 +1102,7 @@ def test_set_forced_variation_when_called_to_remove_forced_variation(self):
 
 
 class ConfigLoggingTest(base.BaseTest):
+
   def setUp(self):
     base.BaseTest.setUp(self)
     self.optimizely = optimizely.Optimizely(json.dumps(self.config_dict),
@@ -1136,14 +1165,25 @@ def test_get_event__invalid_key(self):
 
     mock_config_logging.error.assert_called_once_with('Event "invalid_key" is not in datafile.')
 
-  def test_get_attribute__invalid_key(self):
+  def test_get_attribute_id__invalid_key(self):
     """ Test that message is logged when provided attribute key is invalid. """
 
     with mock.patch.object(self.project_config, 'logger') as mock_config_logging:
-      self.project_config.get_attribute('invalid_key')
+      self.project_config.get_attribute_id('invalid_key')
 
     mock_config_logging.error.assert_called_once_with('Attribute "invalid_key" is not in datafile.')
 
+  def test_get_attribute_id__key_with_opt_prefix_but_not_a_control_attribute(self):
+    """ Test that message is logged when provided attribute key has $opt_ in prefix and
+    key is not one of the control attributes. """
+    self.project_config.attribute_key_map['$opt_abc'] = entities.Attribute('007', '$opt_abc')
+
+    with mock.patch.object(self.project_config, 'logger') as mock_config_logging:
+      self.project_config.get_attribute_id('$opt_abc')
+
+    mock_config_logging.warning.assert_called_once_with(("Attribute $opt_abc unexpectedly has reserved prefix $opt_; "
+                                                         "using attribute ID instead of reserved attribute name."))
+
   def test_get_group__invalid_id(self):
     """ Test that message is logged when provided group ID is invalid. """
 
@@ -1210,12 +1250,12 @@ def test_get_event__invalid_key(self):
                             enums.Errors.INVALID_EVENT_KEY_ERROR,
                             self.project_config.get_event, 'invalid_key')
 
-  def test_get_attribute__invalid_key(self):
+  def test_get_attribute_id__invalid_key(self):
     """ Test that exception is raised when provided attribute key is invalid. """
 
     self.assertRaisesRegexp(exceptions.InvalidAttributeException,
                             enums.Errors.INVALID_ATTRIBUTE_ERROR,
-                            self.project_config.get_attribute, 'invalid_key')
+                            self.project_config.get_attribute_id, 'invalid_key')
 
   def test_get_group__invalid_id(self):
     """ Test that exception is raised when provided group ID is invalid. """
diff --git a/tests/test_event_builder.py b/tests/test_event_builder.py
index 9334e6db..4a74929a 100644
--- a/tests/test_event_builder.py
+++ b/tests/test_event_builder.py
@@ -13,6 +13,7 @@
 
 import mock
 import unittest
+from operator import itemgetter
 
 from optimizely import event_builder
 from optimizely import version
@@ -48,7 +49,13 @@ def _validate_event_object(self, event_obj, expected_url, expected_params, expec
     """ Helper method to validate properties of the event object. """
 
     self.assertEqual(expected_url, event_obj.url)
+
+    expected_params['visitors'][0]['attributes'] = \
+      sorted(expected_params['visitors'][0]['attributes'], key=itemgetter('key'))
+    event_obj.params['visitors'][0]['attributes'] = \
+      sorted(event_obj.params['visitors'][0]['attributes'], key=itemgetter('key'))
     self.assertEqual(expected_params, event_obj.params)
+
     self.assertEqual(expected_verb, event_obj.http_verb)
     self.assertEqual(expected_headers, event_obj.headers)
 
@@ -182,6 +189,166 @@ def test_create_impression_event_when_attribute_is_not_in_datafile(self):
                                   event_builder.EventBuilder.HTTP_VERB,
                                   event_builder.EventBuilder.HTTP_HEADERS)
 
+  def test_create_impression_event__with_user_agent_when_bot_filtering_is_enabled(self):
+    """ Test that create_impression_event creates Event object
+    with right params when user agent attribute is provided and
+    bot filtering is enabled """
+
+    expected_params = {
+      'account_id': '12001',
+      'project_id': '111001',
+      'visitors': [{
+        'visitor_id': 'test_user',
+        'attributes': [{
+          'type': 'custom',
+          'value': 'Edge',
+          'entity_id': '$opt_user_agent',
+          'key': '$opt_user_agent'
+        }, {
+          'type': 'custom',
+          'value': True,
+          'entity_id': '$opt_bot_filtering',
+          'key': '$opt_bot_filtering'
+        }],
+        'snapshots': [{
+          'decisions': [{
+            'variation_id': '111129',
+            'experiment_id': '111127',
+            'campaign_id': '111182'
+          }],
+          'events': [{
+            'timestamp': 42123,
+            'entity_id': '111182',
+            'uuid': 'a68cf1ad-0393-4e18-af87-efe8f01a7c9c',
+            'key': 'campaign_activated'
+          }]
+        }]
+      }],
+      'client_name': 'python-sdk',
+      'client_version': version.__version__,
+      'anonymize_ip': False,
+      'revision': '42'
+    }
+
+    with mock.patch('time.time', return_value=42.123), \
+         mock.patch('uuid.uuid4', return_value='a68cf1ad-0393-4e18-af87-efe8f01a7c9c'),\
+         mock.patch('optimizely.event_builder.EventBuilder._get_bot_filtering', return_value=True):
+      event_obj = self.event_builder.create_impression_event(
+        self.project_config.get_experiment_from_key('test_experiment'),
+        '111129', 'test_user', {'$opt_user_agent': 'Edge'}
+      )
+
+    self._validate_event_object(event_obj,
+                                event_builder.EventBuilder.EVENTS_URL,
+                                expected_params,
+                                event_builder.EventBuilder.HTTP_VERB,
+                                event_builder.EventBuilder.HTTP_HEADERS)
+
+  def test_create_impression_event__with_empty_attributes_when_bot_filtering_is_enabled(self):
+    """ Test that create_impression_event creates Event object
+    with right params when empty attributes are provided and
+    bot filtering is enabled """
+
+    expected_params = {
+      'account_id': '12001',
+      'project_id': '111001',
+      'visitors': [{
+        'visitor_id': 'test_user',
+        'attributes': [{
+          'type': 'custom',
+          'value': True,
+          'entity_id': '$opt_bot_filtering',
+          'key': '$opt_bot_filtering'
+        }],
+        'snapshots': [{
+          'decisions': [{
+            'variation_id': '111129',
+            'experiment_id': '111127',
+            'campaign_id': '111182'
+          }],
+          'events': [{
+            'timestamp': 42123,
+            'entity_id': '111182',
+            'uuid': 'a68cf1ad-0393-4e18-af87-efe8f01a7c9c',
+            'key': 'campaign_activated'
+          }]
+        }]
+      }],
+      'client_name': 'python-sdk',
+      'client_version': version.__version__,
+      'anonymize_ip': False,
+      'revision': '42'
+    }
+
+    with mock.patch('time.time', return_value=42.123), \
+         mock.patch('uuid.uuid4', return_value='a68cf1ad-0393-4e18-af87-efe8f01a7c9c'),\
+         mock.patch('optimizely.event_builder.EventBuilder._get_bot_filtering', return_value=True):
+      event_obj = self.event_builder.create_impression_event(
+        self.project_config.get_experiment_from_key('test_experiment'),
+        '111129', 'test_user', None
+      )
+
+    self._validate_event_object(event_obj,
+                                event_builder.EventBuilder.EVENTS_URL,
+                                expected_params,
+                                event_builder.EventBuilder.HTTP_VERB,
+                                event_builder.EventBuilder.HTTP_HEADERS)
+
+  def test_create_impression_event__with_user_agent_when_bot_filtering_is_disabled(self):
+    """ Test that create_impression_event creates Event object
+    with right params when user agent attribute is provided and
+    bot filtering is disabled """
+
+    expected_params = {
+      'account_id': '12001',
+      'project_id': '111001',
+      'visitors': [{
+        'visitor_id': 'test_user',
+        'attributes': [{
+          'type': 'custom',
+          'value': 'Chrome',
+          'entity_id': '$opt_user_agent',
+          'key': '$opt_user_agent'
+        }, {
+          'type': 'custom',
+          'value': False,
+          'entity_id': '$opt_bot_filtering',
+          'key': '$opt_bot_filtering'
+        }],
+        'snapshots': [{
+          'decisions': [{
+            'variation_id': '111129',
+            'experiment_id': '111127',
+            'campaign_id': '111182'
+          }],
+          'events': [{
+            'timestamp': 42123,
+            'entity_id': '111182',
+            'uuid': 'a68cf1ad-0393-4e18-af87-efe8f01a7c9c',
+            'key': 'campaign_activated'
+          }]
+        }]
+      }],
+      'client_name': 'python-sdk',
+      'client_version': version.__version__,
+      'anonymize_ip': False,
+      'revision': '42'
+    }
+
+    with mock.patch('time.time', return_value=42.123), \
+         mock.patch('uuid.uuid4', return_value='a68cf1ad-0393-4e18-af87-efe8f01a7c9c'),\
+         mock.patch('optimizely.event_builder.EventBuilder._get_bot_filtering', return_value=False):
+      event_obj = self.event_builder.create_impression_event(
+        self.project_config.get_experiment_from_key('test_experiment'),
+        '111129', 'test_user', {'$opt_user_agent': 'Chrome'}
+      )
+
+    self._validate_event_object(event_obj,
+                                event_builder.EventBuilder.EVENTS_URL,
+                                expected_params,
+                                event_builder.EventBuilder.HTTP_VERB,
+                                event_builder.EventBuilder.HTTP_HEADERS)
+
   def test_create_conversion_event(self):
     """ Test that create_conversion_event creates Event object
     with right params when no attributes are provided. """
@@ -269,6 +436,114 @@ def test_create_conversion_event__with_attributes(self):
                                 event_builder.EventBuilder.HTTP_VERB,
                                 event_builder.EventBuilder.HTTP_HEADERS)
 
+  def test_create_conversion_event__with_user_agent_when_bot_filtering_is_enabled(self):
+    """ Test that create_conversion_event creates Event object
+    with right params when user agent attribute is provided and
+    bot filtering is enabled """
+
+    expected_params = {
+      'account_id': '12001',
+      'project_id': '111001',
+      'visitors': [{
+        'visitor_id': 'test_user',
+        'attributes': [{
+          'type': 'custom',
+          'value': 'Edge',
+          'entity_id': '$opt_user_agent',
+          'key': '$opt_user_agent'
+        }, {
+          'type': 'custom',
+          'value': True,
+          'entity_id': '$opt_bot_filtering',
+          'key': '$opt_bot_filtering'
+        }],
+        'snapshots': [{
+          'decisions': [{
+            'variation_id': '111129',
+            'experiment_id': '111127',
+            'campaign_id': '111182'
+          }],
+          'events': [{
+            'timestamp': 42123,
+            'entity_id': '111095',
+            'uuid': 'a68cf1ad-0393-4e18-af87-efe8f01a7c9c',
+            'key': 'test_event'
+          }]
+        }]
+      }],
+      'client_name': 'python-sdk',
+      'client_version': version.__version__,
+      'anonymize_ip': False,
+      'revision': '42'
+    }
+
+    with mock.patch('time.time', return_value=42.123), \
+         mock.patch('uuid.uuid4', return_value='a68cf1ad-0393-4e18-af87-efe8f01a7c9c'), \
+         mock.patch('optimizely.event_builder.EventBuilder._get_bot_filtering', return_value=True):
+      event_obj = self.event_builder.create_conversion_event(
+       'test_event', 'test_user', {'$opt_user_agent': 'Edge'}, None, [('111127', '111129')]
+          )
+
+    self._validate_event_object(event_obj,
+                                event_builder.EventBuilder.EVENTS_URL,
+                                expected_params,
+                                event_builder.EventBuilder.HTTP_VERB,
+                                event_builder.EventBuilder.HTTP_HEADERS)
+
+  def test_create_conversion_event__with_user_agent_when_bot_filtering_is_disabled(self):
+    """ Test that create_conversion_event creates Event object
+    with right params when user agent attribute is provided and
+    bot filtering is disabled """
+
+    expected_params = {
+      'account_id': '12001',
+      'project_id': '111001',
+      'visitors': [{
+        'visitor_id': 'test_user',
+        'attributes': [{
+          'type': 'custom',
+          'value': 'Chrome',
+          'entity_id': '$opt_user_agent',
+          'key': '$opt_user_agent'
+        }, {
+          'type': 'custom',
+          'value': False,
+          'entity_id': '$opt_bot_filtering',
+          'key': '$opt_bot_filtering'
+        }],
+        'snapshots': [{
+          'decisions': [{
+            'variation_id': '111129',
+            'experiment_id': '111127',
+            'campaign_id': '111182'
+          }],
+          'events': [{
+            'timestamp': 42123,
+            'entity_id': '111095',
+            'uuid': 'a68cf1ad-0393-4e18-af87-efe8f01a7c9c',
+            'key': 'test_event'
+          }]
+        }]
+      }],
+      'client_name': 'python-sdk',
+      'client_version': version.__version__,
+      'anonymize_ip': False,
+      'revision': '42'
+    }
+
+    with mock.patch('time.time', return_value=42.123), \
+         mock.patch('uuid.uuid4', return_value='a68cf1ad-0393-4e18-af87-efe8f01a7c9c'), \
+         mock.patch('optimizely.event_builder.EventBuilder._get_bot_filtering', return_value=False):
+      event_obj = self.event_builder.create_conversion_event(
+       'test_event', 'test_user', {'$opt_user_agent': 'Chrome'}, None, [('111127', '111129')]
+          )
+
+    self._validate_event_object(event_obj,
+                                event_builder.EventBuilder.EVENTS_URL,
+                                expected_params,
+                                event_builder.EventBuilder.HTTP_VERB,
+                                event_builder.EventBuilder.HTTP_HEADERS)
+
   def test_create_conversion_event__with_event_tags(self):
     """ Test that create_conversion_event creates Event object
     with right params when event tags are provided. """
diff --git a/tests/test_optimizely.py b/tests/test_optimizely.py
index dd25aa70..f065b051 100644
--- a/tests/test_optimizely.py
+++ b/tests/test_optimizely.py
@@ -13,6 +13,7 @@
 
 import json
 import mock
+from operator import itemgetter
 
 from optimizely import decision_service
 from optimizely import entities
@@ -52,6 +53,11 @@ def _validate_event_object(self, event_obj, expected_url, expected_params, expec
     """ Helper method to validate properties of the event object. """
 
     self.assertEqual(expected_url, event_obj.url)
+
+    expected_params['visitors'][0]['attributes'] = \
+      sorted(expected_params['visitors'][0]['attributes'], key=itemgetter('key'))
+    event_obj.params['visitors'][0]['attributes'] = \
+      sorted(event_obj.params['visitors'][0]['attributes'], key=itemgetter('key'))
     self.assertEqual(expected_params, event_obj.params)
     self.assertEqual(expected_verb, event_obj.http_verb)
     self.assertEqual(expected_headers, event_obj.headers)
@@ -605,6 +611,11 @@ def test_activate__with_attributes__audience_match__bucketing_id_provided(self):
       'visitors': [{
         'visitor_id': 'test_user',
         'attributes': [{
+          'type': 'custom',
+          'value': 'user_bucket_value',
+          'entity_id': '$opt_bucketing_id',
+          'key': '$opt_bucketing_id'
+        }, {
           'type': 'custom',
           'value': 'test_value',
           'entity_id': '111094',
@@ -773,6 +784,11 @@ def test_track__with_attributes__bucketing_id_provided(self):
       'visitors': [{
         'visitor_id': 'test_user',
         'attributes': [{
+          'type': 'custom',
+          'value': 'user_bucket_value',
+          'entity_id': '$opt_bucketing_id',
+          'key': '$opt_bucketing_id'
+        }, {
           'type': 'custom',
           'value': 'test_value',
           'entity_id': '111094',
@@ -1212,7 +1228,12 @@ def test_is_feature_enabled__returns_true_for_feature_experiment_if_feature_enab
       'project_id': '111111',
       'visitors': [{
         'visitor_id': 'test_user',
-        'attributes': [],
+        'attributes': [{
+          'type': 'custom',
+          'value': True,
+          'entity_id': '$opt_bot_filtering',
+          'key': '$opt_bot_filtering'
+        }],
         'snapshots': [{
           'decisions': [{
             'variation_id': '111129',
@@ -1271,7 +1292,12 @@ def test_is_feature_enabled__returns_false_for_feature_experiment_if_feature_dis
       'project_id': '111111',
       'visitors': [{
         'visitor_id': 'test_user',
-        'attributes': [],
+        'attributes': [{
+          'type': 'custom',
+          'value': True,
+          'entity_id': '$opt_bot_filtering',
+          'key': '$opt_bot_filtering'
+        }],
         'snapshots': [{
           'decisions': [{
             'variation_id': '111128',
@@ -1794,6 +1820,7 @@ def test_get_feature_variable__returns_none_if_unable_to_cast(self):
 
 
 class OptimizelyWithExceptionTest(base.BaseTest):
+
   def setUp(self):
     base.BaseTest.setUp(self)
     self.optimizely = optimizely.Optimizely(json.dumps(self.config_dict),
@@ -1825,6 +1852,7 @@ def test_get_variation__with_attributes__invalid_attributes(self):
 
 
 class OptimizelyWithLoggingTest(base.BaseTest):
+
   def setUp(self):
     base.BaseTest.setUp(self)
     self.optimizely = optimizely.Optimizely(