diff --git a/addonpayments/api/card_storage/requests.py b/addonpayments/api/card_storage/requests.py
index 0b1f22b..1ec5dc1 100644
--- a/addonpayments/api/card_storage/requests.py
+++ b/addonpayments/api/card_storage/requests.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import attr
 from attr import ib as Field
 
diff --git a/addonpayments/api/client.py b/addonpayments/api/client.py
index e18db6d..b6fda50 100644
--- a/addonpayments/api/client.py
+++ b/addonpayments/api/client.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import requests
 import attr
 from decouple import config
@@ -58,7 +60,7 @@ def send(self, request, response_validation=True):
             result = requests.post(self.endpoint, data=xml.encode(self.encoding_charset), headers=self.headers)
         except requests.exceptions.RequestException as e:
             error_msg = "POST requests error"
-            logger.error("{}: {}".format(error_msg))
+            logger.error(error_msg)
             raise SdkError(error_msg, e)
 
         normalized_dict = XmlUtils.from_xml_api_response(result.text)
diff --git a/addonpayments/api/common/requests.py b/addonpayments/api/common/requests.py
index e71d2c6..74c9b7b 100644
--- a/addonpayments/api/common/requests.py
+++ b/addonpayments/api/common/requests.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import attr
 from attr import ib as Field
 
diff --git a/addonpayments/api/common/responses.py b/addonpayments/api/common/responses.py
index 2c3c287..2081bf6 100644
--- a/addonpayments/api/common/responses.py
+++ b/addonpayments/api/common/responses.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 from addonpayments.responses import SdkResponse
 
 
diff --git a/addonpayments/api/dcc/requests.py b/addonpayments/api/dcc/requests.py
index 31e7f07..77680ed 100644
--- a/addonpayments/api/dcc/requests.py
+++ b/addonpayments/api/dcc/requests.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import attr
 from attr import ib as Field
 
diff --git a/addonpayments/api/elements.py b/addonpayments/api/elements.py
index 32ca7ec..6a81f81 100644
--- a/addonpayments/api/elements.py
+++ b/addonpayments/api/elements.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import attr
 from attr import ib as Field
 
diff --git a/addonpayments/api/mixins.py b/addonpayments/api/mixins.py
index bfe76b9..773337b 100644
--- a/addonpayments/api/mixins.py
+++ b/addonpayments/api/mixins.py
@@ -1,6 +1,9 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import attr
+import six
 from attr import ib as Field
 
 from addonpayments.mixins import DictMixin
@@ -82,7 +85,7 @@ def normalize_xml(self):
         :return: dict
         """
         result = {}
-        for key, value in self.to_dict().items():
+        for key, value in six.iteritems(self.to_dict()):
             # This field (key) is an object
             if key in self.object_fields:
                 result.update(value.normalize_xml())
diff --git a/addonpayments/api/payment/requests.py b/addonpayments/api/payment/requests.py
index 0f95bcf..af00967 100644
--- a/addonpayments/api/payment/requests.py
+++ b/addonpayments/api/payment/requests.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import attr
 from attr import ib as Field
 
diff --git a/addonpayments/api/tests/conftest.py b/addonpayments/api/tests/conftest.py
index 7bb4dcb..0fdf63c 100644
--- a/addonpayments/api/tests/conftest.py
+++ b/addonpayments/api/tests/conftest.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import pytest
 from decouple import config
 
diff --git a/addonpayments/api/tests/tests/test_card_storage.py b/addonpayments/api/tests/tests/test_card_storage.py
index 02b46f0..0f92e93 100644
--- a/addonpayments/api/tests/tests/test_card_storage.py
+++ b/addonpayments/api/tests/tests/test_card_storage.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import pytest
 
 from addonpayments.api.tests.conftest import BaseTest
diff --git a/addonpayments/api/tests/tests/test_dcc.py b/addonpayments/api/tests/tests/test_dcc.py
index a83e60d..4af8158 100644
--- a/addonpayments/api/tests/tests/test_dcc.py
+++ b/addonpayments/api/tests/tests/test_dcc.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import pytest
 
 from addonpayments.api.tests.conftest import BaseTest
diff --git a/addonpayments/api/tests/tests/test_payment.py b/addonpayments/api/tests/tests/test_payment.py
index 37b292f..9730a37 100644
--- a/addonpayments/api/tests/tests/test_payment.py
+++ b/addonpayments/api/tests/tests/test_payment.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 from addonpayments.api.tests.conftest import BaseTest
 from addonpayments.api.client import ApiClient
 from addonpayments.api.payment.requests import AuthRequest
diff --git a/addonpayments/api/tests/tests/test_three_ds.py b/addonpayments/api/tests/tests/test_three_ds.py
index a8f4118..fbff68f 100644
--- a/addonpayments/api/tests/tests/test_three_ds.py
+++ b/addonpayments/api/tests/tests/test_three_ds.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import pytest
 
 from addonpayments.api.tests.conftest import BaseTest
diff --git a/addonpayments/api/tests/tests/test_transaction_management.py b/addonpayments/api/tests/tests/test_transaction_management.py
index c405f03..ee5d45e 100644
--- a/addonpayments/api/tests/tests/test_transaction_management.py
+++ b/addonpayments/api/tests/tests/test_transaction_management.py
@@ -1,4 +1,7 @@
 # -*- encoding: utf-8 -*-
+
+from __future__ import absolute_import, unicode_literals
+
 import pytest
 
 from addonpayments.api.tests.conftest import BaseTest
diff --git a/addonpayments/api/three_ds/requests.py b/addonpayments/api/three_ds/requests.py
index 0e2ebf2..fcce50d 100644
--- a/addonpayments/api/three_ds/requests.py
+++ b/addonpayments/api/three_ds/requests.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import attr
 from attr import ib as Field
 
diff --git a/addonpayments/api/three_ds/validators.py b/addonpayments/api/three_ds/validators.py
index b92adb3..651ecd8 100644
--- a/addonpayments/api/three_ds/validators.py
+++ b/addonpayments/api/three_ds/validators.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 from addonpayments.utils import ValidateUtils as Validate
 
 
diff --git a/addonpayments/api/transaction_management/requests.py b/addonpayments/api/transaction_management/requests.py
index b5e191f..1629549 100644
--- a/addonpayments/api/transaction_management/requests.py
+++ b/addonpayments/api/transaction_management/requests.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import attr
 from attr import ib as Field
 
diff --git a/addonpayments/api/transaction_management/validators.py b/addonpayments/api/transaction_management/validators.py
index c25667f..00d22e6 100644
--- a/addonpayments/api/transaction_management/validators.py
+++ b/addonpayments/api/transaction_management/validators.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 from addonpayments.utils import ValidateUtils as Validate
 
 
diff --git a/addonpayments/api/utils.py b/addonpayments/api/utils.py
index b3a2ce2..e2bc220 100644
--- a/addonpayments/api/utils.py
+++ b/addonpayments/api/utils.py
@@ -1,5 +1,8 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
+import six
 import xmltodict
 import json
 
@@ -40,7 +43,7 @@ def from_xml_api_response(xml):
         try:
             resp = json.loads(json.dumps(xmltodict.parse(xml)))
             resp['response']
-            response = {key.replace('@', ''): value for key, value in resp['response'].items()}
+            response = {key.replace('@', ''): value for key, value in six.iteritems(resp['response'])}
         except Exception as e:
             error_msg = "Error parsing response XML"
             logger.error("{}: {}".format(error_msg, e))
diff --git a/addonpayments/api/validators.py b/addonpayments/api/validators.py
index 5a766c8..83a549c 100644
--- a/addonpayments/api/validators.py
+++ b/addonpayments/api/validators.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 from addonpayments.utils import ValidateUtils as Validate
 
 
diff --git a/addonpayments/exceptions.py b/addonpayments/exceptions.py
index ce671d1..244542d 100644
--- a/addonpayments/exceptions.py
+++ b/addonpayments/exceptions.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 
 class SdkError(Exception):
     """
diff --git a/addonpayments/hpp/card_storage/requests.py b/addonpayments/hpp/card_storage/requests.py
index 85290d8..906d964 100644
--- a/addonpayments/hpp/card_storage/requests.py
+++ b/addonpayments/hpp/card_storage/requests.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import attr
 from attr import ib as Field
 
diff --git a/addonpayments/hpp/card_storage/validators.py b/addonpayments/hpp/card_storage/validators.py
index 1d9dfcf..923c365 100644
--- a/addonpayments/hpp/card_storage/validators.py
+++ b/addonpayments/hpp/card_storage/validators.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 from addonpayments.utils import ValidateUtils as Validate
 
 
diff --git a/addonpayments/hpp/common/requests.py b/addonpayments/hpp/common/requests.py
index d9df43e..4ce41d8 100644
--- a/addonpayments/hpp/common/requests.py
+++ b/addonpayments/hpp/common/requests.py
@@ -1,6 +1,9 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import attr
+import six
 from attr import ib as Field
 
 from addonpayments.mixins import DictMixin, HashMixin
@@ -65,20 +68,20 @@ def to_dict(self):
         :return: dict
         """
         result = {}
-        for key, value in self.__dict__.items():
+        for key, value in six.iteritems(self.__dict__):
             # Add supplementary data into dict
             if key == 'supplementary_data':
                 try:
-                    for key_supp, value_supp in self.supplementary_data.items():
-                        if key_supp not in self.__dict__.keys():
+                    for key_supp, value_supp in six.iteritems(self.supplementary_data):
+                        if key_supp not in six.iterkeys(self.__dict__):
                             result[key_supp] = value_supp
                 except AttributeError:
                     result[key.upper()] = value
-
-            # Parse boolean fields to str '1' (True) or '0' (False)
-            result_value = self.set_flags(key, value)
-            if result_value:
-                result[key.upper()] = result_value
+            else:
+                # Parse boolean fields to str '1' (True) or '0' (False)
+                result_value = self.set_flags(key, value)
+                if result_value:
+                    result[key.upper()] = result_value
         return result
 
     def hash(self, secret):
diff --git a/addonpayments/hpp/common/responses.py b/addonpayments/hpp/common/responses.py
index 9fb1948..8f66f76 100644
--- a/addonpayments/hpp/common/responses.py
+++ b/addonpayments/hpp/common/responses.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 from addonpayments.responses import SdkResponse
 
 
diff --git a/addonpayments/hpp/hpp.py b/addonpayments/hpp/hpp.py
index 9f2c9b6..e1fda30 100644
--- a/addonpayments/hpp/hpp.py
+++ b/addonpayments/hpp/hpp.py
@@ -1,6 +1,9 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import attr
+import six
 
 from addonpayments.exceptions import SdkError
 from addonpayments.logger import Logger
@@ -143,7 +146,7 @@ def response_from_dict(self, response_dict):
         :return:
         """
         logger.info("Converting dict to HppResponse.")
-        normalized_dict = {key.lower(): value for key, value in response_dict.items()}
+        normalized_dict = {key.lower(): value for key, value in six.iteritems(response_dict)}
         hpp_response = HppResponse(**normalized_dict)
 
         return ValidationUtils.validate_response(hpp_response, self.secret)
diff --git a/addonpayments/hpp/payment/requests.py b/addonpayments/hpp/payment/requests.py
index 54bf70d..4a57b6b 100644
--- a/addonpayments/hpp/payment/requests.py
+++ b/addonpayments/hpp/payment/requests.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import attr
 
 from addonpayments.hpp.common.requests import HppRequest
diff --git a/addonpayments/hpp/tests/conftest.py b/addonpayments/hpp/tests/conftest.py
index 8fa85cb..5526e9d 100644
--- a/addonpayments/hpp/tests/conftest.py
+++ b/addonpayments/hpp/tests/conftest.py
@@ -1,5 +1,8 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
+import codecs
 import pytest
 
 from addonpayments.hpp.card_storage.requests import CardStorageRequest
@@ -30,35 +33,35 @@ def valid_hpp_request_storage_enabled():
 
 @pytest.fixture()
 def json_hpp_payment_request_valid():
-    with open(sample_path(HPP_PAYMENT_REQUEST_VALID_JSON_PATH)) as data_file:
-        yield JsonUtils.from_json_hpp_request(data_file, CHARSET, False)
+    with codecs.open(sample_path(HPP_PAYMENT_REQUEST_VALID_JSON_PATH), 'r', encoding='utf-8') as data_file:
+        yield JsonUtils.from_json_hpp_request(data_file.read(), CHARSET, False)
 
 
 @pytest.fixture()
 def json_hpp_payment_request_supplementary_data():
-    with open(sample_path(HPP_PAYMENT_REQUEST_SUPPLEMENTARY_JSON_PATH)) as data_file:
-        yield JsonUtils.from_json_hpp_request(data_file, CHARSET, False)
+    with codecs.open(sample_path(HPP_PAYMENT_REQUEST_SUPPLEMENTARY_JSON_PATH), 'r', encoding='utf-8') as data_file:
+        yield JsonUtils.from_json_hpp_request(data_file.read(), CHARSET, False)
 
 
 @pytest.fixture()
 def json_hpp_payment_request_encoded():
-    with open(sample_path(HPP_PAYMENT_REQUEST_ENCODED_JSON_PATH)) as data_file:
-        yield JsonUtils.from_json_hpp_request(data_file, CHARSET, True)
+    with codecs.open(sample_path(HPP_PAYMENT_REQUEST_ENCODED_JSON_PATH), 'r', encoding='utf-8') as data_file:
+        yield JsonUtils.from_json_hpp_request(data_file.read(), CHARSET, True)
 
 
 @pytest.fixture()
 def json_hpp_card_storage_request_valid():
-    with open(sample_path(HPP_CARD_STORAGE_REQUEST_VALID_JSON_PATH)) as data_file:
-        yield JsonUtils.from_json_hpp_request(data_file, CHARSET, False)
+    with codecs.open(sample_path(HPP_CARD_STORAGE_REQUEST_VALID_JSON_PATH), 'r', encoding='utf-8') as data_file:
+        yield JsonUtils.from_json_hpp_request(data_file.read(), CHARSET, False)
 
 
 @pytest.fixture()
-def json_hpp_card_storage_request_supplementary_data():
-    with open(sample_path(HPP_CARD_STORAGE_REQUEST_SUPPLEMENTARY_JSON_PATH)) as data_file:
-        yield JsonUtils.from_json_hpp_request(data_file, CHARSET, False)
+def json_hpp_card_storage_request_supp_data():
+    with codecs.open(sample_path(HPP_CARD_STORAGE_REQUEST_SUPPLEMENTARY_JSON_PATH), 'r', encoding='utf-8') as data_file:
+        yield JsonUtils.from_json_hpp_request(data_file.read(), CHARSET, False)
 
 
 @pytest.fixture()
 def json_hpp_card_storage_request_encoded():
-    with open(sample_path(HPP_CARD_STORAGE_REQUEST_ENCODED_JSON_PATH)) as data_file:
-        yield JsonUtils.from_json_hpp_request(data_file, CHARSET, True)
+    with codecs.open(sample_path(HPP_CARD_STORAGE_REQUEST_ENCODED_JSON_PATH), 'r', encoding='utf-8') as data_file:
+        yield JsonUtils.from_json_hpp_request(data_file.read(), CHARSET, True)
diff --git a/addonpayments/hpp/tests/samples/hpp_card_storage_request.json b/addonpayments/hpp/tests/samples/hpp_card_storage_request.json
index f2ebebc..cfc37df 100644
--- a/addonpayments/hpp/tests/samples/hpp_card_storage_request.json
+++ b/addonpayments/hpp/tests/samples/hpp_card_storage_request.json
@@ -9,7 +9,6 @@
   "AUTO_SETTLE_FLAG": "1",
   "COMMENT1": "a-z A-Z 0-9 ' \", + “” ._ - & \\ / @ ! ? % ( )* : £ $ & € # [ ] | = ;ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷ø¤ùúûüýþÿŒŽšœžŸ¥",
   "COMMENT2": "Comment Two",
-  "RETURN_TSS": "0",
   "SHIPPING_CODE": "56|987",
   "SHIPPING_CO": "IRELAND",
   "BILLING_CODE": "123|56",
diff --git a/addonpayments/hpp/tests/samples/hpp_card_storage_request_encoded.json b/addonpayments/hpp/tests/samples/hpp_card_storage_request_encoded.json
index 047175d..00eb595 100644
--- a/addonpayments/hpp/tests/samples/hpp_card_storage_request_encoded.json
+++ b/addonpayments/hpp/tests/samples/hpp_card_storage_request_encoded.json
@@ -9,7 +9,6 @@
   "AUTO_SETTLE_FLAG": "MQ==",
   "COMMENT1": "Q29tbWVudCBUd28=",
   "COMMENT2": "Q29tbWVudCBUd28=",
-  "RETURN_TSS": "MA==",
   "SHIPPING_CODE": "NTZ8OTg3",
   "SHIPPING_CO": "SVJFTEFORA==",
   "BILLING_CODE": "MTIzfDU2",
diff --git a/addonpayments/hpp/tests/samples/hpp_payment_request.json b/addonpayments/hpp/tests/samples/hpp_payment_request.json
index 10557f7..6d556a3 100644
--- a/addonpayments/hpp/tests/samples/hpp_payment_request.json
+++ b/addonpayments/hpp/tests/samples/hpp_payment_request.json
@@ -9,7 +9,6 @@
   "AUTO_SETTLE_FLAG": "1",
   "COMMENT1": "a-z A-Z 0-9 ' \", + “” ._ - & \\ / @ ! ? % ( )* : £ $ & € # [ ] | = ;ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷ø¤ùúûüýþÿŒŽšœžŸ¥",
   "COMMENT2": "Comment Two",
-  "RETURN_TSS": "0",
   "SHIPPING_CODE": "56|987",
   "SHIPPING_CO": "IRELAND",
   "BILLING_CODE": "123|56",
diff --git a/addonpayments/hpp/tests/tests/test_generation_utils.py b/addonpayments/hpp/tests/tests/test_generation_utils.py
index 5ee307a..5d4c36e 100644
--- a/addonpayments/hpp/tests/tests/test_generation_utils.py
+++ b/addonpayments/hpp/tests/tests/test_generation_utils.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import re
 
 from addonpayments.utils import GenerationUtils
diff --git a/addonpayments/hpp/tests/tests/test_hpp_request.py b/addonpayments/hpp/tests/tests/test_hpp_request.py
index 7d6155b..172d111 100644
--- a/addonpayments/hpp/tests/tests/test_hpp_request.py
+++ b/addonpayments/hpp/tests/tests/test_hpp_request.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 
 class TestHppRequest:
     secret = "mysecret"
diff --git a/addonpayments/hpp/tests/tests/test_json_utils.py b/addonpayments/hpp/tests/tests/test_json_utils.py
index 0e3ef7c..0547e1c 100644
--- a/addonpayments/hpp/tests/tests/test_json_utils.py
+++ b/addonpayments/hpp/tests/tests/test_json_utils.py
@@ -1,7 +1,12 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
+import json
+
 from addonpayments.hpp.card_storage.requests import CardStorageRequest
 from addonpayments.hpp.payment.requests import PaymentRequest
+from addonpayments.hpp.utils import JsonUtils
 
 
 class TestJsonUtils:
@@ -33,6 +38,39 @@ def test_from_json_hpp_payment_request(self, json_hpp_payment_request_valid):
         assert json_hpp_payment_request_valid.hpp_lang == "EN"
         assert json_hpp_payment_request_valid.card_payment_button == "Submit Payment"
 
+    def test_to_json_hpp_payment_request(self, json_hpp_payment_request_valid):
+        """
+        Test PaymentRequest generated to JSON
+        :param json_hpp_payment_request_valid: PaymentRequest
+        """
+        assert isinstance(json_hpp_payment_request_valid, PaymentRequest)
+
+        json_base64_request = json.loads(JsonUtils.to_json(json_hpp_payment_request_valid, 'utf-8', True))
+        assert isinstance(json_base64_request, dict)
+        assert json_base64_request.get('TIMESTAMP') == 'MjA5OTAxMDExMjAwMDA='
+        assert json_base64_request.get('ORDER_ID') == 'T3JkZXJJRA=='
+        assert json_base64_request.get('VAR_REF') == 'VmFyaWFibGVSZWY='
+        assert json_base64_request.get('MERCHANT_ID') == 'TWVyY2hhbnRJRA=='
+        assert json_base64_request.get('AMOUNT') == 'MTAw'
+        assert json_base64_request.get('ACCOUNT') == 'bXlBY2NvdW50'
+        assert json_base64_request.get('PROD_ID') == 'UHJvZHVjdElE'
+        assert json_base64_request.get('SHA1HASH') == 'NWQ4ZjA1YWJkNjE4ZTUwZGI0ODYxYTYxY2M5NDAxMTI3ODY0NzRjZg=='
+        comment = 'YS16IEEtWiAwLTkgJyAiLCArIOKAnOKAnSAuXyAtICYgXCAvIEAgISA/ICUgKCApKiA6IMKjICQgJiDigqwgIyBbIF0gfC' \
+                  'A9IDvDgMOBw4LDg8OEw4XDhsOHw4jDicOKw4vDjMONw47Dj8OQw5HDksOTw5TDlcOWw5fDmMOZw5rDm8Ocw53DnsOfw6DD' \
+                  'ocOiw6PDpMOlw6bDp8Oow6nDqsOrw6zDrcOuw6/DsMOxw7LDs8O0w7XDtsO3w7jCpMO5w7rDu8O8w73DvsO/xZLFvcWhxZ' \
+                  'PFvsW4wqU='
+        assert json_base64_request.get('COMMENT1') == comment
+        assert json_base64_request.get('CURRENCY') == 'RVVS'
+        assert json_base64_request.get('SHIPPING_CODE') == 'NTZ8OTg3'
+        assert json_base64_request.get('CARD_PAYMENT_BUTTON') == 'U3VibWl0IFBheW1lbnQ='
+        assert json_base64_request.get('HPP_LANG') == 'RU4='
+        assert json_base64_request.get('AUTO_SETTLE_FLAG') == 'MQ=='
+        assert json_base64_request.get('SHIPPING_CO') == 'SVJFTEFORA=='
+        assert json_base64_request.get('BILLING_CO') == 'SVJFTEFORA=='
+        assert json_base64_request.get('COMMENT2') == 'Q29tbWVudCBUd28='
+        assert json_base64_request.get('BILLING_CODE') == 'MTIzfDU2'
+        assert json_base64_request.get('CUST_NUM') == 'MTIzNDU2'
+
     def test_from_json_hpp_payment_request_supplementary_data(self, json_hpp_payment_request_supplementary_data):
         """
         Test PaymentRequest with supplementary data () generated from JSON
@@ -60,10 +98,44 @@ def test_from_json_hpp_payment_request_supplementary_data(self, json_hpp_payment
         assert json_hpp_payment_request_supplementary_data.hpp_lang == "EN"
         assert json_hpp_payment_request_supplementary_data.card_payment_button == "Submit Payment"
         assert isinstance(json_hpp_payment_request_supplementary_data.supplementary_data, dict)
-        assert json_hpp_payment_request_supplementary_data.supplementary_data['supplementary_1'] == "Supp1"
-        assert json_hpp_payment_request_supplementary_data.supplementary_data['supplementary_2'] == "Supp2"
-        assert json_hpp_payment_request_supplementary_data.supplementary_data['supplementary_3'] == "Supp3"
-        assert json_hpp_payment_request_supplementary_data.supplementary_data['supplementary_4'] == "Supp4"
+        assert json_hpp_payment_request_supplementary_data.supplementary_data['SUPPLEMENTARY_1'] == "Supp1"
+        assert json_hpp_payment_request_supplementary_data.supplementary_data['SUPPLEMENTARY_2'] == "Supp2"
+        assert json_hpp_payment_request_supplementary_data.supplementary_data['SUPPLEMENTARY_3'] == "Supp3"
+        assert json_hpp_payment_request_supplementary_data.supplementary_data['SUPPLEMENTARY_4'] == "Supp4"
+
+    def test_to_json_hpp_payment_request_supplementary_data(self, json_hpp_payment_request_supplementary_data):
+        """
+        Test PaymentRequest with supplementary data () generated to JSON
+        :param json_hpp_payment_request_supplementary_data: PaymentRequest
+        """
+        assert isinstance(json_hpp_payment_request_supplementary_data, PaymentRequest)
+
+        json_base64_request = json.loads(JsonUtils.to_json(json_hpp_payment_request_supplementary_data, 'utf-8', True))
+        assert isinstance(json_base64_request, dict)
+        assert json_base64_request.get('SHIPPING_CO') == 'SVJFTEFORA=='
+        assert json_base64_request.get('HPP_LANG') == 'RU4='
+        assert json_base64_request.get('COMMENT2') == 'Q29tbWVudCBUd28='
+        assert json_base64_request.get('ORDER_ID') == 'T3JkZXJJRA=='
+        assert json_base64_request.get('SHA1HASH') == 'NWQ4ZjA1YWJkNjE4ZTUwZGI0ODYxYTYxY2M5NDAxMTI3ODY0NzRjZg=='
+        assert json_base64_request.get('AUTO_SETTLE_FLAG') == 'MQ=='
+        comment = 'YS16IEEtWiAwLTkgJyAiLCArIOKAnOKAnSAuXyAtICYgXCAvIEAgISA/ICUgKCApKiA6IMKjICQgJiDigqwgIyBbIF0gfCA9'
+        assert json_base64_request.get('COMMENT1') == comment
+        assert json_base64_request.get('VAR_REF') == 'VmFyaWFibGVSZWY='
+        assert json_base64_request.get('TIMESTAMP') == 'MjA5OTAxMDExMjAwMDA='
+        assert json_base64_request.get('ACCOUNT') == 'bXlBY2NvdW50'
+        assert json_base64_request.get('AMOUNT') == 'MTAw'
+        assert json_base64_request.get('SHIPPING_CODE') == 'NTZ8OTg3'
+        assert json_base64_request.get('BILLING_CO') == 'SVJFTEFORA=='
+        assert json_base64_request.get('CUST_NUM') == 'MTIzNDU2'
+        assert json_base64_request.get('CURRENCY') == 'RVVS'
+        assert json_base64_request.get('BILLING_CODE') == 'MTIzfDU2'
+        assert json_base64_request.get('PROD_ID') == 'UHJvZHVjdElE'
+        assert json_base64_request.get('CARD_PAYMENT_BUTTON') == 'U3VibWl0IFBheW1lbnQ='
+        assert json_base64_request.get('MERCHANT_ID') == 'TWVyY2hhbnRJRA=='
+        assert json_base64_request.get('SUPPLEMENTARY_1') == 'U3VwcDE='
+        assert json_base64_request.get('SUPPLEMENTARY_2') == 'U3VwcDI='
+        assert json_base64_request.get('SUPPLEMENTARY_3') == 'U3VwcDM='
+        assert json_base64_request.get('SUPPLEMENTARY_4') == 'U3VwcDQ='
 
     def test_from_json_hpp_payment_request_encoded(self, json_hpp_payment_request_encoded):
         """
@@ -91,7 +163,6 @@ def test_from_json_hpp_payment_request_encoded(self, json_hpp_payment_request_en
         assert json_hpp_payment_request_encoded.hpp_lang == "EN"
         assert json_hpp_payment_request_encoded.card_payment_button == "Submit Payment"
         assert isinstance(json_hpp_payment_request_encoded.supplementary_data, dict)
-        assert json_hpp_payment_request_encoded.supplementary_data['return_tss'] == "0"
 
     def test_from_json_hpp_card_storage_request(self, json_hpp_card_storage_request_valid):
         """
@@ -126,43 +197,118 @@ def test_from_json_hpp_card_storage_request(self, json_hpp_card_storage_request_
         assert json_hpp_card_storage_request_valid.pmt_ref == "PaymentRef"
         assert json_hpp_card_storage_request_valid.payer_exist == "1"
 
-    def test_from_json_hpp_card_storage_request_supplementary_data(self,
-                                                                   json_hpp_card_storage_request_supplementary_data):
+    def test_to_json_hpp_card_storage_request(self, json_hpp_card_storage_request_valid):
+        """
+        Test PaymentRequest generated to JSON
+        :param json_hpp_card_storage_request_valid: PaymentRequest
+        """
+        assert isinstance(json_hpp_card_storage_request_valid, CardStorageRequest)
+
+        json_base64_request = json.loads(JsonUtils.to_json(json_hpp_card_storage_request_valid, 'utf-8', True))
+        assert isinstance(json_base64_request, dict)
+        assert json_base64_request.get('BILLING_CO') == 'SVJFTEFORA=='
+        assert json_base64_request.get('ACCOUNT') == 'bXlBY2NvdW50'
+        assert json_base64_request.get('VAR_REF') == 'VmFyaWFibGVSZWY='
+        assert json_base64_request.get('SHIPPING_CO') == 'SVJFTEFORA=='
+        comment = 'YS16IEEtWiAwLTkgJyAiLCArIOKAnOKAnSAuXyAtICYgXCAvIEAgISA/ICUgKCApKiA6IMKjICQgJiDigqwgIyBbIF0gfCA9I' \
+                  'DvDgMOBw4LDg8OEw4XDhsOHw4jDicOKw4vDjMONw47Dj8OQw5HDksOTw5TDlcOWw5fDmMOZw5rDm8Ocw53DnsOfw6DDocOiw6' \
+                  'PDpMOlw6bDp8Oow6nDqsOrw6zDrcOuw6/DsMOxw7LDs8O0w7XDtsO3w7jCpMO5w7rDu8O8w73DvsO/xZLFvcWhxZPFvsW4wqU='
+        assert json_base64_request.get('COMMENT1') == comment
+        assert json_base64_request.get('COMMENT2') == 'Q29tbWVudCBUd28='
+        assert json_base64_request.get('CURRENCY') == 'RVVS'
+        assert json_base64_request.get('PAYER_EXIST') == 'MQ=='
+        assert json_base64_request.get('MERCHANT_ID') == 'TWVyY2hhbnRJRA=='
+        assert json_base64_request.get('CARD_PAYMENT_BUTTON') == 'U3VibWl0IFBheW1lbnQ='
+        assert json_base64_request.get('ORDER_ID') == 'T3JkZXJJRA=='
+        assert json_base64_request.get('SHIPPING_CODE') == 'NTZ8OTg3'
+        assert json_base64_request.get('AMOUNT') == 'MTAw'
+        assert json_base64_request.get('SHA1HASH') == 'NWQ4ZjA1YWJkNjE4ZTUwZGI0ODYxYTYxY2M5NDAxMTI3ODY0NzRjZg=='
+        assert json_base64_request.get('AUTO_SETTLE_FLAG') == 'MQ=='
+        assert json_base64_request.get('OFFER_SAVE_CARD') == 'MQ=='
+        assert json_base64_request.get('BILLING_CODE') == 'MTIzfDU2'
+        assert json_base64_request.get('PROD_ID') == 'UHJvZHVjdElE'
+        assert json_base64_request.get('PAYER_REF') == 'UGF5ZXJSZWY='
+        assert json_base64_request.get('CARD_STORAGE_ENABLE') == 'MQ=='
+        assert json_base64_request.get('TIMESTAMP') == 'MjA5OTAxMDExMjAwMDA='
+        assert json_base64_request.get('CUST_NUM') == 'MTIzNDU2'
+        assert json_base64_request.get('PMT_REF') == 'UGF5bWVudFJlZg=='
+        assert json_base64_request.get('HPP_LANG') == 'RU4='
+
+    def test_from_json_hpp_card_storage_request_supp_data(self, json_hpp_card_storage_request_supp_data):
         """
         Test CardStorageRequest with supplementary data () generated from JSON
-        :param json_hpp_card_storage_request_supplementary_data: CardStorageRequest
-        """
-        assert isinstance(json_hpp_card_storage_request_supplementary_data, CardStorageRequest)
-        assert json_hpp_card_storage_request_supplementary_data.merchant_id == "MerchantID"
-        assert json_hpp_card_storage_request_supplementary_data.account == "myAccount"
-        assert json_hpp_card_storage_request_supplementary_data.order_id == "OrderID"
-        assert json_hpp_card_storage_request_supplementary_data.amount == "100"
-        assert json_hpp_card_storage_request_supplementary_data.currency == "EUR"
-        assert json_hpp_card_storage_request_supplementary_data.timestamp == "20990101120000"
-        assert json_hpp_card_storage_request_supplementary_data.sha1hash == "5d8f05abd618e50db4861a61cc940112786474cf"
-        assert json_hpp_card_storage_request_supplementary_data.auto_settle_flag == "1"
+        :param json_hpp_card_storage_request_supp_data: CardStorageRequest
+        """
+        assert isinstance(json_hpp_card_storage_request_supp_data, CardStorageRequest)
+        assert json_hpp_card_storage_request_supp_data.merchant_id == "MerchantID"
+        assert json_hpp_card_storage_request_supp_data.account == "myAccount"
+        assert json_hpp_card_storage_request_supp_data.order_id == "OrderID"
+        assert json_hpp_card_storage_request_supp_data.amount == "100"
+        assert json_hpp_card_storage_request_supp_data.currency == "EUR"
+        assert json_hpp_card_storage_request_supp_data.timestamp == "20990101120000"
+        assert json_hpp_card_storage_request_supp_data.sha1hash == "5d8f05abd618e50db4861a61cc940112786474cf"
+        assert json_hpp_card_storage_request_supp_data.auto_settle_flag == "1"
         comment1 = "a-z A-Z 0-9 ' \", + “” ._ - & \\ / @ ! ? % ( )* : £ $ & € # [ ] | ="
-        assert json_hpp_card_storage_request_supplementary_data.comment1 == comment1
-        assert json_hpp_card_storage_request_supplementary_data.comment2 == "Comment Two"
-        assert json_hpp_card_storage_request_supplementary_data.shipping_code == "56|987"
-        assert json_hpp_card_storage_request_supplementary_data.shipping_co == "IRELAND"
-        assert json_hpp_card_storage_request_supplementary_data.billing_code == "123|56"
-        assert json_hpp_card_storage_request_supplementary_data.billing_co == "IRELAND"
-        assert json_hpp_card_storage_request_supplementary_data.cust_num == "123456"
-        assert json_hpp_card_storage_request_supplementary_data.var_ref == "VariableRef"
-        assert json_hpp_card_storage_request_supplementary_data.prod_id == "ProductID"
-        assert json_hpp_card_storage_request_supplementary_data.hpp_lang == "EN"
-        assert json_hpp_card_storage_request_supplementary_data.card_payment_button == "Submit Payment"
-        assert json_hpp_card_storage_request_supplementary_data.card_storage_enable == "1"
-        assert json_hpp_card_storage_request_supplementary_data.offer_save_card == "1"
-        assert json_hpp_card_storage_request_supplementary_data.payer_ref == "PayerRef"
-        assert json_hpp_card_storage_request_supplementary_data.pmt_ref == "PaymentRef"
-        assert json_hpp_card_storage_request_supplementary_data.payer_exist == "1"
-        assert isinstance(json_hpp_card_storage_request_supplementary_data.supplementary_data, dict)
-        assert json_hpp_card_storage_request_supplementary_data.supplementary_data['supplementary_1'] == "Supp1"
-        assert json_hpp_card_storage_request_supplementary_data.supplementary_data['supplementary_2'] == "Supp2"
-        assert json_hpp_card_storage_request_supplementary_data.supplementary_data['supplementary_3'] == "Supp3"
-        assert json_hpp_card_storage_request_supplementary_data.supplementary_data['supplementary_4'] == "Supp4"
+        assert json_hpp_card_storage_request_supp_data.comment1 == comment1
+        assert json_hpp_card_storage_request_supp_data.comment2 == "Comment Two"
+        assert json_hpp_card_storage_request_supp_data.shipping_code == "56|987"
+        assert json_hpp_card_storage_request_supp_data.shipping_co == "IRELAND"
+        assert json_hpp_card_storage_request_supp_data.billing_code == "123|56"
+        assert json_hpp_card_storage_request_supp_data.billing_co == "IRELAND"
+        assert json_hpp_card_storage_request_supp_data.cust_num == "123456"
+        assert json_hpp_card_storage_request_supp_data.var_ref == "VariableRef"
+        assert json_hpp_card_storage_request_supp_data.prod_id == "ProductID"
+        assert json_hpp_card_storage_request_supp_data.hpp_lang == "EN"
+        assert json_hpp_card_storage_request_supp_data.card_payment_button == "Submit Payment"
+        assert json_hpp_card_storage_request_supp_data.card_storage_enable == "1"
+        assert json_hpp_card_storage_request_supp_data.offer_save_card == "1"
+        assert json_hpp_card_storage_request_supp_data.payer_ref == "PayerRef"
+        assert json_hpp_card_storage_request_supp_data.pmt_ref == "PaymentRef"
+        assert json_hpp_card_storage_request_supp_data.payer_exist == "1"
+        assert isinstance(json_hpp_card_storage_request_supp_data.supplementary_data, dict)
+        assert json_hpp_card_storage_request_supp_data.supplementary_data['SUPPLEMENTARY_1'] == "Supp1"
+        assert json_hpp_card_storage_request_supp_data.supplementary_data['SUPPLEMENTARY_2'] == "Supp2"
+        assert json_hpp_card_storage_request_supp_data.supplementary_data['SUPPLEMENTARY_3'] == "Supp3"
+        assert json_hpp_card_storage_request_supp_data.supplementary_data['SUPPLEMENTARY_4'] == "Supp4"
+
+    def test_to_json_hpp_card_storage_request_supp_data(self, json_hpp_card_storage_request_supp_data):
+        """
+        Test CardStorageRequest with supplementary data () generated to JSON
+        :param json_hpp_card_storage_request_supp_data: CardStorageRequest
+        """
+        assert isinstance(json_hpp_card_storage_request_supp_data, CardStorageRequest)
+        json_base64_request = json.loads(JsonUtils.to_json(json_hpp_card_storage_request_supp_data, 'utf-8', True))
+        assert isinstance(json_base64_request, dict)
+
+        assert json_base64_request.get('AUTO_SETTLE_FLAG') == 'MQ=='
+        assert json_base64_request.get('CURRENCY') == 'RVVS'
+        assert json_base64_request.get('PROD_ID') == 'UHJvZHVjdElE'
+        assert json_base64_request.get('SHIPPING_CO') == 'SVJFTEFORA=='
+        assert json_base64_request.get('MERCHANT_ID') == 'TWVyY2hhbnRJRA=='
+        assert json_base64_request.get('ORDER_ID') == 'T3JkZXJJRA=='
+        assert json_base64_request.get('PAYER_EXIST') == 'MQ=='
+        assert json_base64_request.get('PMT_REF') == 'UGF5bWVudFJlZg=='
+        assert json_base64_request.get('AMOUNT') == 'MTAw'
+        assert json_base64_request.get('CUST_NUM') == 'MTIzNDU2'
+        assert json_base64_request.get('COMMENT2') == 'Q29tbWVudCBUd28='
+        assert json_base64_request.get('OFFER_SAVE_CARD') == 'MQ=='
+        assert json_base64_request.get('SHA1HASH') == 'NWQ4ZjA1YWJkNjE4ZTUwZGI0ODYxYTYxY2M5NDAxMTI3ODY0NzRjZg=='
+        assert json_base64_request.get('SHIPPING_CODE') == 'NTZ8OTg3'
+        assert json_base64_request.get('CARD_PAYMENT_BUTTON') == 'U3VibWl0IFBheW1lbnQ='
+        assert json_base64_request.get('HPP_LANG') == 'RU4='
+        assert json_base64_request.get('PAYER_REF') == 'UGF5ZXJSZWY='
+        assert json_base64_request.get('ACCOUNT') == 'bXlBY2NvdW50'
+        comment = 'YS16IEEtWiAwLTkgJyAiLCArIOKAnOKAnSAuXyAtICYgXCAvIEAgISA/ICUgKCApKiA6IMKjICQgJiDigqwgIyBbIF0gfCA9'
+        assert json_base64_request.get('COMMENT1') == comment
+        assert json_base64_request.get('VAR_REF') == 'VmFyaWFibGVSZWY='
+        assert json_base64_request.get('BILLING_CODE') == 'MTIzfDU2'
+        assert json_base64_request.get('CARD_STORAGE_ENABLE') == 'MQ=='
+        assert json_base64_request.get('TIMESTAMP') == 'MjA5OTAxMDExMjAwMDA='
+        assert json_base64_request.get('BILLING_CO') == 'SVJFTEFORA=='
+        assert json_base64_request.get('SUPPLEMENTARY_1') == 'U3VwcDE='
+        assert json_base64_request.get('SUPPLEMENTARY_2') == 'U3VwcDI='
+        assert json_base64_request.get('SUPPLEMENTARY_3') == 'U3VwcDM='
+        assert json_base64_request.get('SUPPLEMENTARY_4') == 'U3VwcDQ='
 
     def test_from_json_hpp_card_storage_request_encoded(self, json_hpp_card_storage_request_encoded):
         """
@@ -193,4 +339,3 @@ def test_from_json_hpp_card_storage_request_encoded(self, json_hpp_card_storage_
         assert json_hpp_card_storage_request_encoded.offer_save_card == "1"
         assert json_hpp_card_storage_request_encoded.payer_exist == "0"
         assert isinstance(json_hpp_card_storage_request_encoded.supplementary_data, dict)
-        assert json_hpp_card_storage_request_encoded.supplementary_data['return_tss'] == "0"
diff --git a/addonpayments/hpp/tests/utils.py b/addonpayments/hpp/tests/utils.py
index 99ca80c..529b48b 100644
--- a/addonpayments/hpp/tests/utils.py
+++ b/addonpayments/hpp/tests/utils.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import os
 
 MERCHANT_ID = 'merchant'
diff --git a/addonpayments/hpp/utils.py b/addonpayments/hpp/utils.py
index 435453d..4ac7911 100644
--- a/addonpayments/hpp/utils.py
+++ b/addonpayments/hpp/utils.py
@@ -1,8 +1,12 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import base64
 import json
 
+import six
+
 from addonpayments.hpp.card_storage.requests import CardStorageRequest
 from addonpayments.hpp.payment.requests import PaymentRequest
 from addonpayments.hpp.common.responses import HppResponse
@@ -39,7 +43,7 @@ def from_json_hpp_request(json_hpp_request, charset, encoded=False):
         :param encoded: bool
         :return: HppRequest
         """
-        obj_request = json.load(json_hpp_request)
+        obj_request = json.loads(json_hpp_request)
         if encoded:
             obj_request = JsonUtils.decode(obj_request, charset)
 
@@ -49,7 +53,8 @@ def from_json_hpp_request(json_hpp_request, charset, encoded=False):
 
         dict_request = {}
         supplementary_data = {}
-        for key, value in obj_request.items():
+
+        for key, value in six.iteritems(obj_request):
             key_hpp = key.lower()
             is_supplementary_data = False
             if is_card_storage:
@@ -59,7 +64,7 @@ def from_json_hpp_request(json_hpp_request, charset, encoded=False):
                 if not hasattr(PaymentRequest, key_hpp):
                     is_supplementary_data = True
             if is_supplementary_data:
-                supplementary_data[key_hpp] = value
+                supplementary_data[key] = value
             else:
                 dict_request[key_hpp] = value
         if supplementary_data:
@@ -91,8 +96,8 @@ def encode(hpp_dict, charset='utf-8'):
         :param charset: string
         :return: dict
         """
-        for key, value in hpp_dict.items():
-            b64_value = base64.b64encode(bytes(str(value), charset))
+        for key, value in six.iteritems(hpp_dict):
+            b64_value = base64.b64encode(six.binary_type(six.text_type(value).encode(charset)))
             hpp_dict[key] = b64_value.decode(charset)
         return hpp_dict
 
@@ -103,8 +108,8 @@ def decode(hpp_dict, charset='utf-8'):
         :param hpp_dict: dict
         :param charset: string
         """
-        for key, value in hpp_dict.items():
-            hpp_dict[key] = str(base64.b64decode(value), charset)
+        for key, value in six.iteritems(hpp_dict):
+            hpp_dict[key] = six.text_type(base64.b64decode(value), charset)
         return hpp_dict
 
     @staticmethod
@@ -114,5 +119,5 @@ def normalize_response(obj_response):
         :type obj_response: dict
         :return: HppResponse
         """
-        obj_response = {key.lower(): value for key, value in obj_response.items()}
+        obj_response = {key.lower(): value for key, value in six.iteritems(obj_response)}
         return HppResponse(**obj_response)
diff --git a/addonpayments/hpp/validators.py b/addonpayments/hpp/validators.py
index ba39653..0a8d018 100644
--- a/addonpayments/hpp/validators.py
+++ b/addonpayments/hpp/validators.py
@@ -1,5 +1,9 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
+import six
+
 from addonpayments.utils import ValidateUtils as Validate
 
 
@@ -192,10 +196,10 @@ def supplementary_data(instance, attribute, value):
         try:
             Validate.validate_dict(attribute.name, value)
             # If value is a dict, convert keys and values to string
-            value = ''.join(['{0}{1}'.format(k, v) for k, v in value.items()])
+            value = ''.join(['{0}{1}'.format(k, v) for k, v in six.iteritems(value)])
         except ValueError:
             Validate.validate_str(attribute.name, value)
-        Validate.validate_length_range(attribute.name, str(value), 0, 255)
+        Validate.validate_length_range(attribute.name, six.text_type(value), 0, 255)
         Validate.validate_regex(
             attribute.name,
             value,
diff --git a/addonpayments/logger.py b/addonpayments/logger.py
index 4ac6e8d..5f054a5 100644
--- a/addonpayments/logger.py
+++ b/addonpayments/logger.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import logging
 
 
diff --git a/addonpayments/mixins.py b/addonpayments/mixins.py
index cf36e75..e61d0cf 100644
--- a/addonpayments/mixins.py
+++ b/addonpayments/mixins.py
@@ -1,5 +1,8 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
+import six
 
 from addonpayments.utils import GenerationUtils
 
@@ -68,4 +71,6 @@ def to_dict(self):
         Return the class attributes in a dictionary
         :return: dict
         """
-        return {key: self.set_flags(key, value) for key, value in self.__dict__.items() if self.set_flags(key, value)}
+        return {
+            key: self.set_flags(key, value) for key, value in six.iteritems(self.__dict__) if self.set_flags(key, value)
+        }
diff --git a/addonpayments/responses.py b/addonpayments/responses.py
index d13f405..6531234 100644
--- a/addonpayments/responses.py
+++ b/addonpayments/responses.py
@@ -1,5 +1,9 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
+import six
+
 from addonpayments.mixins import HashMixin
 
 
@@ -30,7 +34,7 @@ def to_dict(self):
         return the data response as a dictionary
         :return: dict
         """
-        return {key: value for key, value in self.__dict__.items()}
+        return {key: value for key, value in six.iteritems(self.__dict__)}
 
     def hash(self, secret):
         """
diff --git a/addonpayments/utils.py b/addonpayments/utils.py
index 7aa15fd..bd29188 100644
--- a/addonpayments/utils.py
+++ b/addonpayments/utils.py
@@ -1,6 +1,9 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 import re
+import six
 import uuid
 import hashlib
 from datetime import datetime
@@ -29,9 +32,9 @@ def generate_hash(to_hash, secret):
         :return: string
         """
         # Step 1: With the SHA-1 algorithm, obtain the hash value of a string composed of the requested values.
-        to_hash_first_pass = hashlib.sha1(bytes("{}".format(to_hash), encoding="UTF-8")).hexdigest()
+        to_hash_first_pass = hashlib.sha1(six.binary_type(to_hash.encode('utf-8'))).hexdigest()
         # Step 2: Concatenate the hash value chain with the shared secret.
-        return hashlib.sha1(bytes("{}.{}".format(to_hash_first_pass, secret), encoding="UTF-8")).hexdigest()
+        return hashlib.sha1(six.binary_type("{}.{}".format(to_hash_first_pass, secret).encode('utf-8'))).hexdigest()
 
     def generate_order_id(self):
         """
@@ -43,7 +46,7 @@ def generate_order_id(self):
 
     def generate_timestamp(self):
         """
-        Generate the current datetimestamp in the string format (YYYYMMDDHHSS) required in a request.
+        Generate the current date timestamp in the string format (YYYYMMDDHHSS) required in a request.
         :return: string
         """
         return datetime.now().strftime(self.date_format)
@@ -90,7 +93,7 @@ def validate_str(name, value):
         :param name: string
         :param value:
         """
-        if not isinstance(value, str):
+        if not isinstance(value, six.string_types):
             raise ValueError("{} must be string".format(name))
 
     @staticmethod
diff --git a/addonpayments/validators.py b/addonpayments/validators.py
index 67f4a6a..e35dd6f 100644
--- a/addonpayments/validators.py
+++ b/addonpayments/validators.py
@@ -1,5 +1,7 @@
 # -*- encoding: utf-8 -*-
 
+from __future__ import absolute_import, unicode_literals
+
 from addonpayments.utils import ValidateUtils as Validate
 
 
diff --git a/requirements.txt b/requirements.txt
index 959fa03..8bc47eb 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,13 +1,27 @@
--e git+git@gitlab.apsl.net:addonpayments/addonpayments-sdk-python.git@8014e0137721442a268b681f76486f13bde8776d#egg=addonpayments_sdk_python
+apipkg==1.4
 appdirs==1.4.2
+attr==0.2.0
 attrs==16.3.0
+eradicate==0.1.6
+execnet==1.4.1
+flake8==3.3.0
+mccabe==0.6.1
 packaging==16.8
 pluggy==0.4.0
 py==1.4.32
+pycodestyle==2.3.1
+pyflakes==1.5.0
 pyparsing==2.1.10
+pytest==3.0.6
+pytest-cache==1.0
+pytest-eradicate==0.0.3
+pytest-flake8==0.8.1
+pytest-sugar==0.8.0
 python-decouple==3.0
 requests==2.13.0
 six==1.10.0
+termcolor==1.1.0
 tox==2.6.0
 virtualenv==15.1.0
 xmltodict==0.10.2
+future==0.16.0
diff --git a/setup.py b/setup.py
index df74f68..3ca25ae 100644
--- a/setup.py
+++ b/setup.py
@@ -1,6 +1,8 @@
-import os
-import re
-import codecs
+# -*- encoding: utf-8 -*-
+
+# import os
+# import re
+# import codecs
 
 try:
     from setuptools import setup, find_packages
@@ -12,24 +14,27 @@ def get_version(package):
     """
     Return package version as listed in `__version__` in `init.py`.
     """
-    init_py = codecs.open(os.path.join(package, '__init__.py'), encoding='utf-8').read()
-    return re.search("^__version__ = ['\"]([^'\"]+)['\"]", init_py, re.MULTILINE).group(1)
+    return "0.1"
+    # init_py = codecs.open(os.path.abspath(os.path.join(package, '__init__.py')), encoding='utf-8').read()
+    # return re.search("^__version__ = ['\"]([^'\"]+)['\"]", init_py, re.MULTILINE).group(1)
 
 
 def get_author(package):
     """
     Return package author as listed in `__author__` in `init.py`.
     """
-    init_py = codecs.open(os.path.join(package, '__init__.py'), encoding='utf-8').read()
-    return re.search("^__author__ = ['\"]([^'\"]+)['\"]", init_py, re.MULTILINE).group(1)
+    return "Marc Galofré"
+    # init_py = codecs.open(os.path.abspath(os.path.join(package, '__init__.py')), encoding='utf-8').read()
+    # return re.search("^__author__ = ['\"]([^'\"]+)['\"]", init_py, re.MULTILINE).group(1)
 
 
 def get_email(package):
     """
     Return package email as listed in `__email__` in `init.py`.
     """
-    init_py = codecs.open(os.path.join(package, '__init__.py'), encoding='utf-8').read()
-    return re.search("^__email__ = ['\"]([^'\"]+)['\"]", init_py, re.MULTILINE).group(1)
+    return "mgalofre@apsl.net"
+    # init_py = codecs.open(os.path.abspath(os.path.join(package, '__init__.py')), encoding='utf-8').read()
+    # return re.search("^__email__ = ['\"]([^'\"]+)['\"]", init_py, re.MULTILINE).group(1)
 
 
 setup(
@@ -39,12 +44,14 @@ def get_email(package):
     include_package_data=True,
     keywords="addonpayments sdk python hpp api",
     description='A SDK Addonpayments implemented with Python.',
-    long_description=codecs.open(os.path.join(os.path.dirname(__file__), 'README.rst'), encoding='utf-8').read(),
+    # long_description=codecs.open(os.path.join(os.path.dirname(__file__), 'README.rst'), encoding='utf-8').read(),
+    long_description='',
     install_requires=[
         'python-decouple',
         'attrs',
         'xmltodict',
         'requests',
+        'future'
     ],
     url='https://gitlab.apsl.net/addonpayments/addonpayments-sdk-python',
     author=get_author('addonpayments'),
diff --git a/tox.ini b/tox.ini
index 2fc2ece..e822d58 100644
--- a/tox.ini
+++ b/tox.ini
@@ -12,8 +12,6 @@ commands =
 
 basepython =
     py27: python2.7
-    py33: python3.3
-    py34: python3.4
     py35: python3.5
 
 deps =
@@ -21,6 +19,8 @@ deps =
     pytest-sugar==0.8.0
     pytest-flake8==0.8.1
     pytest-eradicate==0.0.3
+    python-decouple==3.0.0
+    future==0.16.0
 
 [testenv:flake8]
 basepython = python3.5