diff --git a/Configuration/AppConfigurationManager.py b/Configuration/AppConfigurationManager.py
new file mode 100644
index 0000000..37bf950
--- /dev/null
+++ b/Configuration/AppConfigurationManager.py
@@ -0,0 +1,11 @@
+from Models.AppConfiguration import AppConfiguration
+import json
+
+class AppConfigurationManager:
+    appConfiguration: AppConfiguration = None
+
+    def __init__(self):
+        with open('./appconfig.json', 'rb') as appConfigurationFile:
+
+            appConfiguration = json.load(appConfigurationFile)
+            self.appConfiguration = AppConfiguration(appConfiguration['deviceConfigurationLocalFilePath'])
diff --git a/Configuration/DeviceConfigurationManager.py b/Configuration/DeviceConfigurationManager.py
new file mode 100644
index 0000000..02ed56b
--- /dev/null
+++ b/Configuration/DeviceConfigurationManager.py
@@ -0,0 +1,70 @@
+import os.path
+from Models.DeviceConfiguration import *
+from trashtech_api import *
+from Configuration.AppConfigurationManager import AppConfigurationManager
+
+class DeviceConfigurationManager:
+    _configFilePath: str = ''
+    _deviceConfiguration: DeviceConfiguration = None
+    _trashtechApi: TrashtechApi = None
+
+    def __init__(self, trashtechApi: TrashtechApi, appConfigurationManager: AppConfigurationManager):
+
+        if trashtechApi is None:
+            raise ValueError('ConfigurationManager: Class initialization with not initialized trashtechApi')
+
+        if appConfigurationManager is None:
+            raise ValueError('ConfigurationManager: Class initialization with not initialized appConfigurationManager')
+
+        self._configFilePath = appConfigurationManager.appConfiguration.deviceConfigurationLocalFilePath
+        self._trashtechApi = trashtechApi
+
+    def LoadFromFile(self) -> DeviceConfiguration:
+        try:
+            if os.path.isfile(self._configFilePath):
+                with open(self._configFilePath, "rb") as configFile:
+                    data = json.load(configFile)
+
+                    self._deviceConfiguration = DeviceConfiguration(data['photo_interval'],
+                                                                    data['photo_rotation'],
+                                                                    data['photo_width'],
+                                                                    data['photo_height'],
+                                                                    data['custom_resolution'])
+                    return self._deviceConfiguration
+            else:
+                return None
+        except IOError as e:
+            return None
+
+    def TryGetDeviceConfiguration(self) -> DeviceConfiguration:
+
+        if self._deviceConfiguration is not None:
+            return self._deviceConfiguration
+        else:
+            localConfig = self.LoadFromFile()
+
+            if localConfig is not None:
+                self._deviceConfiguration = localConfig
+                return self._deviceConfiguration
+            else:
+                self._deviceConfiguration = self._trashtechApi.GetConfiguration()
+
+                if self._deviceConfiguration is None:
+                    return None
+
+                self.SaveConfiguration()
+                return self._deviceConfiguration
+
+    def SaveConfiguration(self):
+
+        if self._deviceConfiguration is None:
+            return False
+
+        try:
+
+            with open(self._configFilePath, 'w') as outfile:
+                json.dump(self._deviceConfiguration, outfile, default=lambda o: o.__dict__)
+                return True
+
+        except Exception as e:
+            return False
diff --git a/Models/AppConfiguration.py b/Models/AppConfiguration.py
new file mode 100644
index 0000000..92825ee
--- /dev/null
+++ b/Models/AppConfiguration.py
@@ -0,0 +1,8 @@
+
+
+class AppConfiguration:
+
+    deviceConfigurationLocalFilePath: str = ''
+
+    def __init__(self, deviceConfigurationLocalFilePath: str):
+        self.deviceConfigurationLocalFilePath = deviceConfigurationLocalFilePath
\ No newline at end of file
diff --git a/Models/DeviceConfiguration.py b/Models/DeviceConfiguration.py
new file mode 100644
index 0000000..137ff8d
--- /dev/null
+++ b/Models/DeviceConfiguration.py
@@ -0,0 +1,22 @@
+
+
+class DeviceConfiguration:
+
+    photo_interval: int = -1
+    photo_rotation: int = -1
+    photo_width: int = -1
+    photo_height: int = -1
+    custom_resolution: bool = False
+
+    def __init__(self,
+                 photo_interval,
+                 photo_rotation,
+                 photo_width,
+                 photo_height,
+                 custom_resolution):
+
+        self.photo_interval = photo_interval
+        self.photo_rotation = photo_rotation
+        self.photo_width = photo_width
+        self.photo_height = photo_height
+        self.custom_resolution = custom_resolution
\ No newline at end of file
diff --git a/Tests/Resources/DeviceConfigurationSnapshot.json b/Tests/Resources/DeviceConfigurationSnapshot.json
new file mode 100644
index 0000000..3f83d9a
--- /dev/null
+++ b/Tests/Resources/DeviceConfigurationSnapshot.json
@@ -0,0 +1 @@
+{"photo_interval": 3600, "photo_rotation": 0, "photo_width": 640, "photo_height": 480, "custom_resolution": true}
\ No newline at end of file
diff --git a/Tests/manual b/Tests/manual
new file mode 100644
index 0000000..89f9a41
--- /dev/null
+++ b/Tests/manual
@@ -0,0 +1,5 @@
+Crate file with unit tests cases:
+-file name should follow this convention test_*.py
+
+
+python -m pytest tests/ - run this command to run all tests from tests directory
\ No newline at end of file
diff --git a/Tests/test_DeviceConfigurationManager.py b/Tests/test_DeviceConfigurationManager.py
new file mode 100644
index 0000000..729bbca
--- /dev/null
+++ b/Tests/test_DeviceConfigurationManager.py
@@ -0,0 +1,136 @@
+import pytest
+from Configuration.DeviceConfigurationManager import *
+from Configuration.AppConfigurationManager import *
+from trashtech_api import *
+
+
+class TestConfigurationManager:
+
+    def test_LoadFromFile_NoneTrashtechApiParameter_Invalid(self):
+        with pytest.raises(Exception):
+            # Arange
+            trashtechApi = None
+
+            # Act + Assert
+            assert DeviceConfigurationManager(trashtechApi, None)
+
+    def test_LoadFromFile_NoneAppConfigurationManagerParameter_Invalid(self):
+        with pytest.raises(Exception):
+            # Arange
+            trashtechApi = TrashtechApi()
+            appConfigurationManager = None
+
+            # Act + Assert
+            assert DeviceConfigurationManager(trashtechApi, appConfigurationManager)
+
+    def test_LoadFromFile_FileDoesNotExsist_Valid(self):
+
+        # Arange
+        trashtechApi = TrashtechApi()
+        appConfigurationManager = AppConfigurationManager()
+
+        appConfigurationManager.appConfiguration.deviceConfigurationLocalFilePath = 'blabla.json'
+
+        deviceConfigurationManager = DeviceConfigurationManager(trashtechApi, appConfigurationManager)
+
+        # Act
+        deviceConfiguration = deviceConfigurationManager.LoadFromFile()
+
+        # assert
+        assert deviceConfiguration is None
+
+    def test_LoadFromFile_FileExsist_Valid(self):
+        # Arange
+        trashtechApi = TrashtechApi()
+        appConfigurationManager = AppConfigurationManager()
+
+        appConfigurationManager.appConfiguration.deviceConfigurationLocalFilePath = './Tests/Resources/DeviceConfigurationSnapshot.json'
+
+        deviceConfigurationManager = DeviceConfigurationManager(trashtechApi, appConfigurationManager)
+
+        # Act
+        deviceConfiguration = deviceConfigurationManager.LoadFromFile()
+
+        # assert
+        assert deviceConfiguration is not None
+        assert isinstance(deviceConfiguration, DeviceConfiguration)
+
+    def test_SaveConfiguration_DeviceConfigLoaded_Valid(self):
+
+        # Arange
+        trashtechApi = TrashtechApi()
+        appConfigurationManager = AppConfigurationManager()
+
+        appConfigurationManager.appConfiguration.deviceConfigurationLocalFilePath = './Tests/Resources/DeviceConfigurationSnapshot.json'
+
+        deviceConfigurationManager = DeviceConfigurationManager(trashtechApi, appConfigurationManager)
+        deviceConfiguration = deviceConfigurationManager.LoadFromFile()
+
+        # Act
+        saveResult = deviceConfigurationManager.SaveConfiguration()
+
+        # assert
+        assert saveResult is True
+
+    def test_SaveConfiguration_NoneDeviceConfig_Invalid(self):
+            # Arange
+            trashtechApi = TrashtechApi()
+            appConfigurationManager = AppConfigurationManager()
+
+            appConfigurationManager.appConfiguration.deviceConfigurationLocalFilePath = './Tests/Resources/DeviceConfigurationSnapshot.json'
+
+            deviceConfigurationManager = DeviceConfigurationManager(trashtechApi, appConfigurationManager)
+
+            # Act
+            saveResult = deviceConfigurationManager.SaveConfiguration()
+
+            # assert
+            assert saveResult is False
+
+    def test_TryGetDeviceConfiguration_DeviceConfigLoadedAlready_Valid(self):
+        # Arange
+        trashtechApi = TrashtechApi()
+        appConfigurationManager = AppConfigurationManager()
+
+        appConfigurationManager.appConfiguration.deviceConfigurationLocalFilePath = './Tests/Resources/DeviceConfigurationSnapshot.json'
+
+        deviceConfigurationManager = DeviceConfigurationManager(trashtechApi, appConfigurationManager)
+        deviceConfiguration = deviceConfigurationManager.LoadFromFile()
+
+        # Act
+        deviceConfiguration = deviceConfigurationManager.TryGetDeviceConfiguration()
+
+        # assert
+        assert deviceConfiguration is not None
+
+    def test_TryGetDeviceConfiguration_DeviceConfigLoadedFromDisk_Valid(self):
+        # Arange
+        trashtechApi = TrashtechApi()
+        appConfigurationManager = AppConfigurationManager()
+
+        appConfigurationManager.appConfiguration.deviceConfigurationLocalFilePath = './Tests/Resources/DeviceConfigurationSnapshot.json'
+
+        deviceConfigurationManager = DeviceConfigurationManager(trashtechApi, appConfigurationManager)
+
+        # Act
+        deviceConfiguration = deviceConfigurationManager.TryGetDeviceConfiguration()
+
+        # assert
+        assert deviceConfiguration is not None
+
+    def test_TryGetDeviceConfiguration_DeviceConfigLoadedFromNetwork_Valid(self):
+        # Arange
+        trashtechApi = TrashtechApi()
+        appConfigurationManager = AppConfigurationManager()
+
+        appConfigurationManager.appConfiguration.deviceConfigurationLocalFilePath = './Tests/Resources/DeviceConfigurationSnapshot1.json'
+
+        deviceConfigurationManager = DeviceConfigurationManager(trashtechApi, appConfigurationManager)
+
+        # Act
+        deviceConfiguration = deviceConfigurationManager.TryGetDeviceConfiguration()
+
+        # assert
+        assert deviceConfiguration is not None
+
+        os.remove(appConfigurationManager.appConfiguration.deviceConfigurationLocalFilePath)
diff --git a/Tests/test_TrashtechApi.py b/Tests/test_TrashtechApi.py
new file mode 100644
index 0000000..7f38238
--- /dev/null
+++ b/Tests/test_TrashtechApi.py
@@ -0,0 +1,15 @@
+import pytest
+from trashtech_api import *
+
+
+class TestTrashTechApi:
+
+    def test_GetConfiguration(self):
+        # Arrange
+        trashtechApi = TrashtechApi()
+
+        # Act
+        configuration = trashtechApi.GetConfiguration()
+
+        # Assert
+        assert configuration is not None
diff --git a/Tests/test_foo.py b/Tests/test_foo.py
new file mode 100644
index 0000000..2db00a2
--- /dev/null
+++ b/Tests/test_foo.py
@@ -0,0 +1,7 @@
+import pytest
+
+def func(x):
+    return x + 1
+
+def test_answer():
+    assert func(3) == 4
\ No newline at end of file
diff --git a/appconfig.json b/appconfig.json
new file mode 100644
index 0000000..11cfd13
--- /dev/null
+++ b/appconfig.json
@@ -0,0 +1,3 @@
+{
+  "deviceConfigurationLocalFilePath": "./DeviceConfigurationSnapshot.json"
+}
\ No newline at end of file
diff --git a/main.py b/main.py
index dc410ca..1ea1b2b 100644
--- a/main.py
+++ b/main.py
@@ -5,80 +5,92 @@
 import logging
 
 from snap import Snapper
-from trashtech_api import TrashtechApi
 from gsm_controller import GsmController
+from Configuration.DeviceConfigurationManager import *
+from Configuration.AppConfigurationManager import *
 
 DEVICE_REFERENCE = '000006'
 FILE_FORMAT = "%s/TT_%s.jpg"
 TIMESTAMP_FORMAT = '%Y-%m-%d %H:%M:%S'
 
+
 class TrashtechApp:
-  def initialize(self):
-    self.trashtech_client = TrashtechApi()
-    self.snapper = Snapper()
-    self.gsm_controller = GsmController()
+    _trashtech_client: TrashtechApi = None
+    _deviceConfigurationManager: DeviceConfigurationManager = None
+    _snapper: Snapper = None
+    _gsm_controller: GsmController = None
+    _configuration: DeviceConfiguration = None
+
+    def initialize(self):
+        self._trashtech_client = TrashtechApi()
+        appManager = AppConfigurationManager()
+
+        self._deviceConfigurationManager = DeviceConfigurationManager(self._trashtech_client, appManager)
+        self._snapper = Snapper()
+        self._gsm_controller = GsmController()
+
+    def retrive_configuration(self):
+        self._configuration = self._deviceConfigurationManager.TryGetDeviceConfiguration()
+        self._snapper.set_resolution(self._configuration.photo_width, self._configuration.photo_height)
 
-  def retrive_configuration(self):
-    self.configuration = self.trashtech_client.configuration()
-    self.snapper.set_resolution(self.configuration['photo_width'], self.configuration['photo_height'])
+    def interval(self):
+        return self._configuration.photo_interval
 
-  def interval(self):
-    return self.configuration['photo_interval']
+    def call_snap(self, filename):
+        self._snapper.snap(filename)
 
-  def call_snap(self, filename):
-    self.snapper.snap(filename)
+    def init_gsm(self):
+        if self._gsm_controller.is_ppp_interface_present() is not True:
+            self._gsm_controller.enable()
 
-  def init_gsm(self):
-    if self.gsm_controller.is_ppp_interface_present() is not True:
-      self.gsm_controller.enable()
+    def wait_for_gsm(self):
+        while self._gsm_controller.is_ppp_interface_present() is not True:
+            logging.info("[INFO] Waiting for GSM..")
+            time.sleep(2)
 
-  def wait_for_gsm(self):
-    while self.gsm_controller.is_ppp_interface_present() is not True:
-      logging.info("[INFO] Waiting for GSM..")
-      time.sleep(2)
+        if self._gsm_controller.is_ppp_interface_present():
+            logging.info("[INFO] GSM module enabled")
 
-    if self.gsm_controller.is_ppp_interface_present():
-      logging.info("[INFO] GSM module enabled")
+        time.sleep(5)
 
-    time.sleep(5)
+    def run(self):
+        start_time = time.time()
 
-  def run(self):
-    start_time = time.time()
+        self.init_gsm()
 
-    self.init_gsm()
+        image_created_at_timestamp = time.time()
+        complete_file_path = FILE_FORMAT % ('images', image_created_at_timestamp)
 
-    image_created_at_timestamp = time.time()
-    complete_file_path = FILE_FORMAT % ('images', image_created_at_timestamp)
+        self.call_snap(complete_file_path)
+        self.wait_for_gsm()
 
-    self.call_snap(complete_file_path)
-    self.wait_for_gsm()
+        image_created_at = datetime.datetime.fromtimestamp(image_created_at_timestamp).strftime(TIMESTAMP_FORMAT)
+        self._trashtech_client.create_status(DEVICE_REFERENCE, complete_file_path, image_created_at)
 
-    image_created_at = datetime.datetime.fromtimestamp(image_created_at_timestamp).strftime(TIMESTAMP_FORMAT)
-    self.trashtech_client.create_status(DEVICE_REFERENCE, complete_file_path, image_created_at)
+        self._gsm_controller.disable()
+        logging.info("[INFO] GSM module disabled")
 
-    self.gsm_controller.disable()
-    logging.info("[INFO] GSM module disabled")
+        execution_time = time.time() - start_time
+        logging.info("[INFO] Execution time: %s" % execution_time)
 
-    execution_time = time.time() - start_time
-    logging.info("[INFO] Execution time: %s" % execution_time)
+        wait_iterval_time = int(float(self.interval()) - execution_time)
+        logging.info("[INFO] Wait interval time: %s" % wait_iterval_time)
 
-    wait_iterval_time = int(float(self.interval()) - execution_time)
-    logging.info("[INFO] Wait interval time: %s" % wait_iterval_time)
+        thread = threading.Timer(wait_iterval_time, trashtech_app.run)
+        thread.start()
 
-    thread = threading.Timer(wait_iterval_time, trashtech_app.run)
-    thread.start()
 
 if __name__ == '__main__':
-  logging.basicConfig(
-    format='[INFO] %(asctime)s - %(message)s',
-    level=logging.INFO
-  )
-
-  logging.info("Hi. We are TRASHTECH. Let's play.")
-
-  trashtech_app = TrashtechApp()
-  trashtech_app.initialize()
-  trashtech_app.init_gsm()
-  trashtech_app.wait_for_gsm()
-  trashtech_app.retrive_configuration()
-  trashtech_app.run()
+    logging.basicConfig(
+        format='[INFO] %(asctime)s - %(message)s',
+        level=logging.INFO
+    )
+
+    logging.info("Hi. We are TRASHTECH. Let's play.")
+
+    trashtech_app = TrashtechApp()
+    trashtech_app.initialize()
+    trashtech_app.init_gsm()
+    trashtech_app.wait_for_gsm()
+    trashtech_app.retrive_configuration()
+    trashtech_app.run()
diff --git a/trashtech_api.py b/trashtech_api.py
index 70598b4..c1a1652 100644
--- a/trashtech_api.py
+++ b/trashtech_api.py
@@ -8,7 +8,7 @@
 class TrashtechApi:
   api_base = 'http://trashtech.herokuapp.com/api'
 
-  def configuration(self):
+  def GetConfiguration(self):
     url = "%s/device_configurations/1" % self.api_base
     logging.info('[INFO] request call: %s' % url)