diff --git a/.travis.yml b/.travis.yml
index 4a43456..00f7484 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,6 +15,10 @@ matrix:
       env: TOXENV=py35
     - python: 3.6
       env: TOXENV=py36
+    - python: pypy
+      env: TOXENV=pypy
+    - python: pypy3.5
+      env: TOXENV=pypy3
 
 install:
   - pip install tox
diff --git a/logzio/handler.py b/logzio/handler.py
index 0b319f3..a4c741f 100644
--- a/logzio/handler.py
+++ b/logzio/handler.py
@@ -32,6 +32,9 @@ class LogzioHandler(logging.Handler):
             backup_logs=backup_logs)
         logging.Handler.__init__(self)
 
+    def __del__(self):
+        del self.logzio_sender
+
     def extra_fields(self, message):
 
         not_allowed_keys = (
diff --git a/logzio/sender.py b/logzio/sender.py
index 6e81b26..922d266 100644
--- a/logzio/sender.py
+++ b/logzio/sender.py
@@ -48,6 +48,11 @@ class LogzioSender:
         self.queue = queue.Queue()
         self._initialize_sending_thread()
 
+    def __del__(self):
+        del self.logger
+        del self.backup_logs
+        del self.queue
+
     def _initialize_sending_thread(self):
         self.sending_thread = Thread(target=self._drain_queue)
         self.sending_thread.daemon = False
@@ -153,12 +158,19 @@ class LogzioSender:
                     'backing up to local file system', number_of_retries)
                 backup_logs(logs_list, self.logger)
 
+            del logs_list
+
     def _get_messages_up_to_max_allowed_size(self):
         logs_list = []
         current_size = 0
         while not self.queue.empty():
             current_log = self.queue.get()
-            current_size += sys.getsizeof(current_log)
+            try:
+                current_size += sys.getsizeof(current_log)
+            except TypeError:
+                # pypy do not support sys.getsizeof
+                current_size += len(current_log) * 4
+
             logs_list.append(current_log)
             if current_size >= MAX_BULK_SIZE_IN_BYTES:
                 break
diff --git a/tox.ini b/tox.ini
index 57794c0..7604e50 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 minversion = 1.7.2
-envlist = flake8, py3flake8, py27, py34, py35, py36
+envlist = flake8, py3flake8, py27, py34, py35, py36, pypy, pypy3
 skip_missing_interpreters = true
 
 [testenv]