diff --git a/.gitignore b/.gitignore
index b3d2a18..cfb49d7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -101,3 +101,4 @@ ENV/
 .mypy_cache/
 
 .idea
+downloaded
diff --git a/Pipfile b/Pipfile
new file mode 100644
index 0000000..85adddd
--- /dev/null
+++ b/Pipfile
@@ -0,0 +1,16 @@
+[[source]]
+url = "https://pypi.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[packages]
+requests = "==2.20.0"
+python-dotenv = "==0.6.4"
+google-api-python-client = "==1.6.2"
+httplib2 = "*"
+PyJWT = "*"
+
+[dev-packages]
+
+[requires]
+python_version = "3.6"
diff --git a/Pipfile.lock b/Pipfile.lock
new file mode 100644
index 0000000..590e847
--- /dev/null
+++ b/Pipfile.lock
@@ -0,0 +1,173 @@
+{
+    "_meta": {
+        "hash": {
+            "sha256": "af911aaf6bce10dd84596ccd20fc28d271d1eea5286b35a50311d071900ae76a"
+        },
+        "pipfile-spec": 6,
+        "requires": {
+            "python_version": "3.6"
+        },
+        "sources": [
+            {
+                "name": "pypi",
+                "url": "https://pypi.org/simple",
+                "verify_ssl": true
+            }
+        ]
+    },
+    "default": {
+        "certifi": {
+            "hashes": [
+                "sha256:1a4995114262bffbc2413b159f2a1a480c969de6e6eb13ee966d470af86af59c",
+                "sha256:719a74fb9e33b9bd44cc7f3a8d94bc35e4049deebe19ba7d8e108280cfd59830"
+            ],
+            "version": "==2020.12.5"
+        },
+        "chardet": {
+            "hashes": [
+                "sha256:84ab92ed1c4d4f16916e05906b6b75a6c0fb5db821cc65e70cbd64a3e2a5eaae",
+                "sha256:fc323ffcaeaed0e0a02bf4d117757b98aed530d9ed4531e3e15460124c106691"
+            ],
+            "version": "==3.0.4"
+        },
+        "click": {
+            "hashes": [
+                "sha256:7d8c289ee437bcb0316820ccee14aefcb056e58d31830ecab8e47eda6540e136",
+                "sha256:e90e62ced43dc8105fb9a26d62f0d9340b5c8db053a814e25d95c19873ae87db"
+            ],
+            "markers": "python_version >= '3.6'",
+            "version": "==8.0.0"
+        },
+        "google-api-python-client": {
+            "hashes": [
+                "sha256:8c2f50f8057571a5f817c74820cadb754d47799c5a4ea463c1500fe8e092c1ae",
+                "sha256:c0f4bcf398c937a43f382eecb384ba9b3a97ef9c24b156420b1b396fcaadd0af"
+            ],
+            "index": "pypi",
+            "version": "==1.6.2"
+        },
+        "httplib2": {
+            "hashes": [
+                "sha256:0b12617eeca7433d4c396a100eaecfa4b08ee99aa881e6df6e257a7aad5d533d",
+                "sha256:2ad195faf9faf079723f6714926e9a9061f694d07724b846658ce08d40f522b4"
+            ],
+            "index": "pypi",
+            "version": "==0.19.1"
+        },
+        "idna": {
+            "hashes": [
+                "sha256:156a6814fb5ac1fc6850fb002e0852d56c0c8d2531923a51032d1b70760e186e",
+                "sha256:684a38a6f903c1d71d6d5fac066b58d7768af4de2b832e426ec79c30daa94a16"
+            ],
+            "version": "==2.7"
+        },
+        "oauth2client": {
+            "hashes": [
+                "sha256:b8a81cc5d60e2d364f0b1b98f958dbd472887acaf1a5b05e21c28c31a2d6d3ac",
+                "sha256:d486741e451287f69568a4d26d70d9acd73a2bbfa275746c535b4209891cccc6"
+            ],
+            "version": "==4.1.3"
+        },
+        "pyasn1": {
+            "hashes": [
+                "sha256:014c0e9976956a08139dc0712ae195324a75e142284d5f87f1a87ee1b068a359",
+                "sha256:03840c999ba71680a131cfaee6fab142e1ed9bbd9c693e285cc6aca0d555e576",
+                "sha256:0458773cfe65b153891ac249bcf1b5f8f320b7c2ce462151f8fa74de8934becf",
+                "sha256:08c3c53b75eaa48d71cf8c710312316392ed40899cb34710d092e96745a358b7",
+                "sha256:39c7e2ec30515947ff4e87fb6f456dfc6e84857d34be479c9d4a4ba4bf46aa5d",
+                "sha256:5c9414dcfede6e441f7e8f81b43b34e834731003427e5b09e4e00e3172a10f00",
+                "sha256:6e7545f1a61025a4e58bb336952c5061697da694db1cae97b116e9c46abcf7c8",
+                "sha256:78fa6da68ed2727915c4767bb386ab32cdba863caa7dbe473eaae45f9959da86",
+                "sha256:7ab8a544af125fb704feadb008c99a88805126fb525280b2270bb25cc1d78a12",
+                "sha256:99fcc3c8d804d1bc6d9a099921e39d827026409a58f2a720dcdb89374ea0c776",
+                "sha256:aef77c9fb94a3ac588e87841208bdec464471d9871bd5050a287cc9a475cd0ba",
+                "sha256:e89bf84b5437b532b0803ba5c9a5e054d21fec423a89952a74f87fa2c9b7bce2",
+                "sha256:fec3e9d8e36808a28efb59b489e4528c10ad0f480e57dcc32b4de5c9d8c9fdf3"
+            ],
+            "version": "==0.4.8"
+        },
+        "pyasn1-modules": {
+            "hashes": [
+                "sha256:0845a5582f6a02bb3e1bde9ecfc4bfcae6ec3210dd270522fee602365430c3f8",
+                "sha256:0fe1b68d1e486a1ed5473f1302bd991c1611d319bba158e98b106ff86e1d7199",
+                "sha256:15b7c67fabc7fc240d87fb9aabf999cf82311a6d6fb2c70d00d3d0604878c811",
+                "sha256:426edb7a5e8879f1ec54a1864f16b882c2837bfd06eee62f2c982315ee2473ed",
+                "sha256:65cebbaffc913f4fe9e4808735c95ea22d7a7775646ab690518c056784bc21b4",
+                "sha256:905f84c712230b2c592c19470d3ca8d552de726050d1d1716282a1f6146be65e",
+                "sha256:a50b808ffeb97cb3601dd25981f6b016cbb3d31fbf57a8b8a87428e6158d0c74",
+                "sha256:a99324196732f53093a84c4369c996713eb8c89d360a496b599fb1a9c47fc3eb",
+                "sha256:b80486a6c77252ea3a3e9b1e360bc9cf28eaac41263d173c032581ad2f20fe45",
+                "sha256:c29a5e5cc7a3f05926aff34e097e84f8589cd790ce0ed41b67aed6857b26aafd",
+                "sha256:cbac4bc38d117f2a49aeedec4407d23e8866ea4ac27ff2cf7fb3e5b570df19e0",
+                "sha256:f39edd8c4ecaa4556e989147ebf219227e2cd2e8a43c7e7fcb1f1c18c5fd6a3d",
+                "sha256:fe0644d9ab041506b62782e92b06b8c68cca799e1a9636ec398675459e031405"
+            ],
+            "version": "==0.2.8"
+        },
+        "pyjwt": {
+            "hashes": [
+                "sha256:934d73fbba91b0483d3857d1aff50e96b2a892384ee2c17417ed3203f173fca1",
+                "sha256:fba44e7898bbca160a2b2b501f492824fc8382485d3a6f11ba5d0c1937ce6130"
+            ],
+            "index": "pypi",
+            "version": "==2.1.0"
+        },
+        "pyparsing": {
+            "hashes": [
+                "sha256:c203ec8783bf771a155b207279b9bccb8dea02d8f0c9e5f8ead507bc3246ecc1",
+                "sha256:ef9d7589ef3c200abe66653d3f1ab1033c3c419ae9b9bdb1240a85b024efc88b"
+            ],
+            "markers": "python_version >= '2.6' and python_version not in '3.0, 3.1, 3.2'",
+            "version": "==2.4.7"
+        },
+        "python-dotenv": {
+            "hashes": [
+                "sha256:bac21323df7ab51765948442392872e0ad89cc5c9122ab7f41bd8ad689fc7c72",
+                "sha256:db38f9e42a7bb53c68d0aa3ce97c18b62250dc21b64896be27246dfb96315d55"
+            ],
+            "index": "pypi",
+            "version": "==0.6.4"
+        },
+        "requests": {
+            "hashes": [
+                "sha256:99dcfdaaeb17caf6e526f32b6a7b780461512ab3f1d992187801694cba42770c",
+                "sha256:a84b8c9ab6239b578f22d1c21d51b696dcfe004032bb80ea832398d6909d7279"
+            ],
+            "index": "pypi",
+            "version": "==2.20.0"
+        },
+        "rsa": {
+            "hashes": [
+                "sha256:78f9a9bf4e7be0c5ded4583326e7461e3a3c5aae24073648b4bdfa797d78c9d2",
+                "sha256:9d689e6ca1b3038bc82bf8d23e944b6b6037bc02301a574935b2dd946e0353b9"
+            ],
+            "markers": "python_version >= '3.5' and python_version < '4'",
+            "version": "==4.7.2"
+        },
+        "six": {
+            "hashes": [
+                "sha256:1e61c37477a1626458e36f7b1d82aa5c9b094fa4802892072e49de9c60c4c926",
+                "sha256:8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254"
+            ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2'",
+            "version": "==1.16.0"
+        },
+        "uritemplate": {
+            "hashes": [
+                "sha256:07620c3f3f8eed1f12600845892b0e036a2420acf513c53f7de0abd911a5894f",
+                "sha256:5af8ad10cec94f215e3f48112de2022e1d5a37ed427fbd88652fa908f2ab7cae"
+            ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'",
+            "version": "==3.0.1"
+        },
+        "urllib3": {
+            "hashes": [
+                "sha256:2393a695cd12afedd0dcb26fe5d50d0cf248e5a66f75dbd89a3d4eb333a61af4",
+                "sha256:a637e5fae88995b256e3409dc4d52c2e2e0ba32c42a6365fee8bbd2238de3cfb"
+            ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3' and python_version < '4'",
+            "version": "==1.24.3"
+        }
+    },
+    "develop": {}
+}
diff --git a/src/settings.py b/src/settings.py
index 8e85763..153c35a 100644
--- a/src/settings.py
+++ b/src/settings.py
@@ -17,11 +17,12 @@
 ZOOM_API_KEY = os.environ.get("ZOOM_API_KEY")
 ZOOM_API_SECRET = os.environ.get("ZOOM_API_SECRET")
 ZOOM_FROM_DAY_DELTA = int(os.environ.get("ZOOM_FROM_DAY_DELTA") or 7)
+ZOOM_PAGE_SIZE = int(os.environ.get("ZOOM_PAGE_SIZE") or 10)
 
 VIDEO_DIR = join(BASE_DIR, 'video')
 
 SLACK_TOKEN = os.environ.get('SLACK_TOKEN')
-SLACK_CHANNEL = os.environ.get('SLACK_CHANNEL')
+SLACK_CHANNEL = os.environ.get('SLACK_CHANNEL', '')
 SLACK_CHANNELS_UNIQUE_SETTINGS = {}  # Example: {'lesson_1': ['#main', '#lessons']}
 NOT_SEND_MSG_TO_PUBLIC_CHANNEL_FOR_MEETINGS = [
     n.strip() for n in os.environ.get("NOT_SEND_MSG_TO_PUBLIC_CHANNEL_FOR_MEETINGS", "").split(",")
@@ -32,10 +33,8 @@
 DOWNLOADED_FILES = join(BASE_DIR, 'downloaded')
 LOCK_FILE = join(BASE_DIR, 'lock')
 
-
-WEBHOOK_BACKEND_PIPELINES = [
-    'webhooks.backends.slack.SlackClient',
-]
+DEFAULT_WEBHOOK_BACKEND = 'webhooks.backends.slack.SlackClient'
+WEBHOOK_BACKEND_PIPELINES = [b for b in os.environ.get('WEBHOOK_BACKEND_PIPELINE', DEFAULT_WEBHOOK_BACKEND).split(',') if b]
 
 MIN_DURATION = int(os.environ.get('MIN_DURATION') or 10)  # minute
 
diff --git a/src/webhooks/backends/slack.py b/src/webhooks/backends/slack.py
index 3413040..c8aeb81 100644
--- a/src/webhooks/backends/slack.py
+++ b/src/webhooks/backends/slack.py
@@ -11,7 +11,7 @@ class SlackClient(WebHookBase):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.chat_url = urljoin(self.BASE_URL, 'chat.postMessage')
-        self.channels = [ch.strip() for ch in SLACK_CHANNEL.split(',')]
+        self.channels = [ch.strip() for ch in SLACK_CHANNEL.split(',') if ch]
         self.channels_unique_settings = SLACK_CHANNELS_UNIQUE_SETTINGS
         self.bot_name = 'zoom2youtube'
         self.token = SLACK_TOKEN
diff --git a/src/zoom.py b/src/zoom.py
index 3eb59ad..ecd3e28 100644
--- a/src/zoom.py
+++ b/src/zoom.py
@@ -64,12 +64,13 @@ def __init__(
         self.filter_meeting_by_name = filter_meeting_by_name
         self.only_meeting_names = only_meeting_names or []
         self.from_day_delta = from_day_delta
+        self.page_size = page_size
 
     def get_meetings(self):
         uri = "users/{}/recordings?from={}&page_size={}".format(
             self.email,
             (datetime.utcnow() - timedelta(days=self.from_day_delta)).strftime("%Y-%m-%d"),
-            page_size
+            self.page_size
         )
         resp = self.client.get(uri)
         if resp.status_code != 200: