diff --git a/apptuit/apptuit_client.py b/apptuit/apptuit_client.py
index 42a6802..5246b3b 100644
--- a/apptuit/apptuit_client.py
+++ b/apptuit/apptuit_client.py
@@ -101,6 +101,7 @@ def __init__(self, token=None, api_endpoint="https://api.apptuit.ai",
         self._global_tags = global_tags
         if not self._global_tags and not ignore_environ_tags:
             self._global_tags = _get_tags_from_environment()
+        self.session = requests.Session()
 
     @property
     def put_apiurl(self):
@@ -205,7 +206,7 @@ def __send(self, payload, points_count, timeout):
         headers["Content-Type"] = "application/json"
         headers["Content-Encoding"] = "deflate"
         headers["User-Agent"] = _get_user_agent()
-        response = requests.post(self.put_apiurl, data=body, headers=headers, timeout=timeout)
+        response = self.session.post(self.put_apiurl, data=body, headers=headers, timeout=timeout)
         if response.status_code != 200 and response.status_code != 204:
             status_code = response.status_code
             if status_code == 400:
@@ -269,7 +270,7 @@ def _execute_query(self, query_string, start, end, timeout):
         headers["User-Agent"] = _get_user_agent()
         if self.token:
             headers["Authorization"] = "Bearer " + self.token
-        hresp = requests.get(query_string, headers=headers, timeout=timeout)
+        hresp = self.session.get(query_string, headers=headers, timeout=timeout)
         body = hresp.content
         return _parse_response(body, start, end)
 
diff --git a/apptuit/utils.py b/apptuit/utils.py
index e569585..3b47d21 100644
--- a/apptuit/utils.py
+++ b/apptuit/utils.py
@@ -10,11 +10,11 @@
 VALID_CHARSET = set(ascii_letters + digits + "-_./")
 INVALID_CHARSET = frozenset(map(chr, range(128))) - VALID_CHARSET
 
-def _contains_valid_chars(string):
-    return INVALID_CHARSET.isdisjoint(string)
+def _contains_valid_chars(val):
+    return INVALID_CHARSET.isdisjoint(val)
 
 def _validate_tags(tags):
-    for tagk, tagv in tags.items():
+    for tagk in tags.keys():
         if not tagk or not _contains_valid_chars(tagk):
             raise ValueError("Tag key %s contains an invalid character, "
                              "allowed characters are a-z, A-Z, 0-9, -, _, ., and /" % tagk)
diff --git a/tests/test_pyformance_reporter.py b/tests/test_pyformance_reporter.py
index 3ce06b7..cd238bf 100644
--- a/tests/test_pyformance_reporter.py
+++ b/tests/test_pyformance_reporter.py
@@ -17,7 +17,7 @@
 except ImportError:
     from mock import Mock, patch
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_batch_send(mock_post):
     """
         Test that when we create more than BATCH_SIZE number of points
@@ -42,7 +42,7 @@ def test_batch_send(mock_post):
     assert_equals(total_points_sent, points_to_be_created)
 
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_partially_successful_send(mock_post):
     """
         Test that we handle partially successful sends
@@ -73,7 +73,7 @@ def test_partially_successful_send(mock_post):
     assert_equals(failed_points_count, 2)
 
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_send_negative(mock_post):
     """
         Test negative responce from Apptuit backend
@@ -98,7 +98,7 @@ def test_send_negative(mock_post):
     with assert_raises(ApptuitSendException):
         reporter.report_now()
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_reporter_thread_active(mock_post):
     """
         Test that reporter thread is active even if we are not able to send data
@@ -120,7 +120,7 @@ def test_reporter_thread_active(mock_post):
     time.sleep(3)
     assert_greater_equal(mock_post.call_count, 2)
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_invalid_metric_name(mock_post):
     """
         Test for invalid metric name when reporting data
@@ -141,7 +141,7 @@ def test_invalid_metric_name(mock_post):
     with assert_raises(ValueError) as ex:
         reporter._collect_data_points(reporter.registry, None)
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_invalid_tag(mock_post):
     """
         Test for invalid tag key when reporting data
@@ -178,7 +178,7 @@ def test_invalid_registry():
     with assert_raises(AttributeError) as ex:
         reporter._collect_data_points(None, None)
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_tags_with_key(mock_post):
     """
         Test that additions tags work
@@ -198,7 +198,7 @@ def test_tags_with_key(mock_post):
         cpu.add(random.randint(i, 100))
     reporter.report_now()
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_tags_with_key_invalid(mock_post):
     """
             Test that invalid tags raise error
@@ -234,12 +234,12 @@ def test_calling_report_now():
                                tags=tags)
     counter_test = registry.counter("counter")
     counter_test.inc(2)
-    with patch('apptuit.apptuit_client.requests.post') as mock_method:
+    with patch('apptuit.apptuit_client.requests.Session.post') as mock_method:
         mock_method.return_value.status_code = 200
         reporter.report_now()
         assert_equals(mock_method.called, True)
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_zero_tags(mock_post):
     """
         Test that using reporter without tags does not raise error
@@ -257,7 +257,7 @@ def test_zero_tags(mock_post):
     counter_test.inc(2)
     reporter.report_now()
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_zero_tags_with_host_disabled(mock_post):
     """
         Test that using reporter without tags raises error
@@ -412,7 +412,7 @@ def test_none_prefix():
     dps = reporter._collect_data_points(reporter.registry)
     assert_equals(dps[0].metric, "counter1.count")
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_meta_metrics_of_reporter(mock_post):
     """
     Test that meta metrics of reporter work
diff --git a/tests/test_query.py b/tests/test_query.py
index d74cc60..212bb12 100644
--- a/tests/test_query.py
+++ b/tests/test_query.py
@@ -43,7 +43,7 @@ def do_query(mock_get):
     end = 1407609000
     return client.query(query, start, end)
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_query(mock_get):
     """
     Test a valid query and make sure results are returned
@@ -51,7 +51,7 @@ def test_query(mock_get):
     resp = do_query(mock_get)
     assert_is_not_none(resp[0])
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_query_result_number_index(mock_get):
     """
     Test that we can access the output by number based indexing from
@@ -61,7 +61,7 @@ def test_query_result_number_index(mock_get):
     df = resp[0].to_df()
     assert_is_not_none(df)
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_query_result_string_index(mock_get):
     """
     Test that we can access the output by the name of the metric from the
@@ -71,7 +71,7 @@ def test_query_result_string_index(mock_get):
     df = resp["nyc.taxi.rides"].to_df()
     assert_is_not_none(df)
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_df_shape(mock_get):
     """
     Verify the dataframe shape
@@ -80,7 +80,7 @@ def test_df_shape(mock_get):
     df = resp[0].to_df()
     assert_equals(df.shape, (432, 1))
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_number_of_series(mock_get):
     """
     Verify the number of time series in the query result
@@ -88,7 +88,7 @@ def test_number_of_series(mock_get):
     resp = do_query(mock_get)
     assert_equals(len(resp[0].series), 1)
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_data(mock_get):
     """
     Verify the data returned from the query
@@ -98,7 +98,7 @@ def test_data(mock_get):
     df = resp[0].to_df()
     assert_true(df.equals(expected_df))
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_metadata(mock_get):
     """
     Test that the metadata of the query results are as expected
@@ -110,7 +110,7 @@ def test_metadata(mock_get):
     assert_equals(series.name.metric, expected_series_name)
     assert_equals(series.name.tags, expected_tags)
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_multiple_retries(mock_get):
     """
     Test that the query API attempts retries when an error is returned from
@@ -128,7 +128,7 @@ def test_multiple_retries(mock_get):
     with assert_raises(ApptuitException):
         client.query(query, start, end, retry_count=3)
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_get_error(mock_get):
     """
     Test that when the retry_count is 0 for the query API we get an exception
@@ -144,7 +144,7 @@ def test_get_error(mock_get):
     with assert_raises(ApptuitException):
         client.query(query, start, end, retry_count=0)
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_invalid_metric_name(mock_get):
     """
     Test that we get an exception if the metric name contains invalid characters
@@ -199,7 +199,7 @@ def test_invalid_metric_name(mock_get):
     with assert_raises(ValueError):
         client.query(query, start, end)
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_empty_dps(mock_get):
     """
     Test that we get an exception if the dps array is empty in the JSON response
@@ -253,7 +253,7 @@ def test_empty_dps(mock_get):
     client.query(query, start, end)
 
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_empty_output(mock_get):
     """
     Test the case when the outputs array is empty in the response
@@ -306,7 +306,7 @@ def test_empty_output(mock_get):
     resp = client.query(query, start, end)
     assert_is_none(resp)
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_empty_results(mock_get):
     """
     Test that when results array is empty in the response and we try to access the
@@ -368,7 +368,7 @@ def test_empty_results(mock_get):
     with assert_raises(KeyError):
         _ = resp[0]
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_tags_dict_type(mock_get):
     """
     Test that an exception is raised if the tags returned in the response
@@ -429,7 +429,7 @@ def test_tags_dict_type(mock_get):
     with assert_raises(ValueError):
         client.query(query, start, end)
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_invalid_char_in_tag_key(mock_get):
     """
     Test for invalid character in one of the tag keys in the response
@@ -491,7 +491,7 @@ def test_invalid_char_in_tag_key(mock_get):
     with assert_raises(ValueError):
         client.query(query, start, end)
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_invalid_char_in_tag_value(mock_get):
     """
     Test for invalid character in tag value in the response
@@ -570,7 +570,7 @@ def test_timeseries_obj_creation():
     with assert_raises(ValueError):
         apptuit_client.TimeSeries(metric=None, tags=None)
 
-@patch('apptuit.apptuit_client.requests.get')
+@patch('apptuit.apptuit_client.requests.Session.get')
 def test_missing_pandas(mock_get):
     orig_modules = sys.modules.copy()
     orig_pandas = orig_modules['pandas']
diff --git a/tests/test_send.py b/tests/test_send.py
index 07398fe..721c4f0 100644
--- a/tests/test_send.py
+++ b/tests/test_send.py
@@ -41,7 +41,7 @@ def test_client_global_tags():
     mock_environ.stop()
 
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_send_positive(mock_post):
     """
     Test that send API is working as expected
@@ -65,7 +65,7 @@ def test_send_positive(mock_post):
     if dps:
         client.send(dps)
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_send_server_error(mock_post):
     """
     Test for the case when there is an error from the backend for send
@@ -87,7 +87,7 @@ def test_send_server_error(mock_post):
         if points_sent > 500:
             break
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_send_413_error(mock_post):
     """
     Test for the case when we get 413 from the PUT API
@@ -251,7 +251,7 @@ def test_apptuit_send_exception_without_status():
                        "datapoint test\n")
 
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_apptuit_send_exception_400(mock_post):
     """
     Test for the case when there is an error from the backend for send
@@ -265,7 +265,7 @@ def test_apptuit_send_exception_400(mock_post):
     with assert_raises(ApptuitSendException):
         client.send(dps)
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_apptuit_send_exception_401(mock_post):
     """
     Test for the case when there is an error from the backend for send
@@ -387,7 +387,7 @@ def test_timeseries_payload_with_envtags():
     assert_equals(expected_payload, payload)
 
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_send_timeseries(mock_post):
     """
     Test the send_timeseries API
@@ -411,7 +411,7 @@ def test_send_timeseries(mock_post):
     series_list.append(series2)
     client.send_timeseries(series_list)
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_send_timeseries_empty(mock_post):
     """
     Test the send_timeseries API with an empty series list
@@ -442,7 +442,7 @@ def test_datapoint_repr():
     assert_equals(repr(point), expected_repr)
     assert_equals(str(point), expected_repr)
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_tags_limit_direct(mock_post):
     """
     Test for failure when too many tags are used for datapoints/series
@@ -461,7 +461,7 @@ def test_tags_limit_direct(mock_post):
     with assert_raises(ValueError):
         client.send_timeseries([series1, series2])
 
-@patch('apptuit.apptuit_client.requests.post')
+@patch('apptuit.apptuit_client.requests.Session.post')
 def test_tags_limit_indirect(mock_post):
     """
     Test for failure when too many tags are used indirectly (when combined with global tags)