diff --git a/customerio/__init__.py b/customerio/__init__.py
index 252383d..eb16ce1 100644
--- a/customerio/__init__.py
+++ b/customerio/__init__.py
@@ -3,6 +3,7 @@
 import math
 import time
 import warnings
+import json
 
 from requests import Session
 from requests.adapters import HTTPAdapter
@@ -19,6 +20,27 @@ class CustomerIOException(Exception):
     pass
 
 
+class CustomJSONEncoder(json.JSONEncoder):
+    def _datetime_to_timestamp(self, dt):
+        if USE_PY3_TIMESTAMPS:
+            return int(dt.replace(tzinfo=timezone.utc).timestamp())
+        else:
+            return int(time.mktime(dt.timetuple()))
+
+    def default(self, obj):
+        ''' Add special handling for data types not supported by the standard json library.
+
+        :param obj: Value being serialized to JSON
+        :return: The serialized value as a native python type.
+        '''
+        if isinstance(obj, datetime):
+            return self._datetime_to_timestamp(obj)
+        if isinstance(obj, float) and math.isnan(obj):
+            return None
+
+        return json.JSONEncoder.default(self, obj)
+
+
 class CustomerIO(object):
 
     def __init__(self, site_id=None, api_key=None, host=None, port=None, url_prefix=None, json_encoder=None, retries=3, timeout=10, backoff_factor=0.02):
@@ -74,7 +96,12 @@ def send_request(self, method, url, data):
         '''Dispatches the request and returns a response'''
 
         try:
-            response = self.http.request(method, url=url, json=self._sanitize(data), timeout=self.timeout)
+            response = self.http.request(
+                method,
+                url=url,
+                data=json.dumps(data, cls=CustomJSONEncoder),
+                timeout=self.timeout,
+            )
         except Exception as e:
             # Raise exception alerting user that the system might be
             # experiencing an outage and refer them to system status page.
@@ -117,14 +144,6 @@ def backfill(self, customer_id, name, timestamp, **data):
         '''Backfill an event (track with timestamp) for a given customer_id'''
         url = self.get_event_query_string(customer_id)
 
-        if isinstance(timestamp, datetime):
-            timestamp = self._datetime_to_timestamp(timestamp)
-        elif not isinstance(timestamp, int):
-            try:
-                timestamp = int(timestamp)
-            except Exception as e:
-                raise CustomerIOException("{t} is not a valid timestamp ({err})".format(t=timestamp, err=e))
-
         post_data = {
             'name': name,
             'data': data,
@@ -205,20 +224,6 @@ def remove_from_segment(self, segment_id, customer_ids):
         payload = {'ids': self._stringify_list(customer_ids)}
         self.send_request('POST', url, payload)
 
-    def _sanitize(self, data):
-        for k, v in data.items():
-            if isinstance(v, datetime):
-                data[k] = self._datetime_to_timestamp(v)
-            if isinstance(v, float) and math.isnan(v):
-                data[k] = None
-        return data
-
-    def _datetime_to_timestamp(self, dt):
-        if USE_PY3_TIMESTAMPS:
-            return int(dt.replace(tzinfo=timezone.utc).timestamp())
-        else:
-            return int(time.mktime(dt.timetuple()))
-
     def _stringify_list(self, customer_ids):
         customer_string_ids = []
         for v in customer_ids: