diff --git a/shiftregister/messaging/backends/clicksend.py b/shiftregister/messaging/backends/clicksend.py
index 5fdb7a7..5a8419a 100644
--- a/shiftregister/messaging/backends/clicksend.py
+++ b/shiftregister/messaging/backends/clicksend.py
@@ -2,9 +2,13 @@ import json
 from ast import literal_eval
 from datetime import datetime, timezone
 
-from clicksend_client import ApiClient
-from clicksend_client import Configuration as BaseConfiguration
-from clicksend_client import SMSApi, SmsMessage, SmsMessageCollection
+from clicksend_client import (
+    ApiClient,
+    Configuration,
+    SMSApi,
+    SmsMessage,
+    SmsMessageCollection,
+)
 from clicksend_client.rest import ApiException
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
@@ -19,29 +23,6 @@ __all__ = ("Receiver", "Sender")
 MAX_BATCH_SIZE = 1000  # see https://developers.clicksend.com/docs/rest/v3/#how-many-messages-can-i-send
 
 
-class Configuration(BaseConfiguration):
-    def __init__(self):
-        super().__init__()
-
-        for setting in (
-            "clicksend_password",
-            "clicksend_sender_id",
-            "clicksend_username",
-        ):
-            try:
-                settings.SMS_SETTINGS[setting]
-            except KeyError:
-                raise ImproperlyConfigured(
-                    f"'{setting}' must be set in SMS_SETTINGS for ClickSend backend"
-                )
-
-        self.username = settings.SMS_SETTINGS["clicksend_username"]
-        self.password = settings.SMS_SETTINGS["clicksend_password"]
-
-
-client = ApiClient(Configuration())
-
-
 class Receiver(BaseReceiver):
     fetch = None
 
@@ -66,11 +47,30 @@ class Receiver(BaseReceiver):
 
 
 class Sender(BaseSender):
+    def __init__(self):
+        for setting in (
+            "clicksend_password",
+            "clicksend_sender_id",
+            "clicksend_username",
+        ):
+            try:
+                settings.SMS_SETTINGS[setting]
+            except KeyError:
+                raise ImproperlyConfigured(
+                    f"'{setting}' must be set in SMS_SETTINGS for ClickSend backend"
+                )
+
+        config = Configuration()
+        config.username = settings.SMS_SETTINGS["clicksend_username"]
+        config.password = settings.SMS_SETTINGS["clicksend_password"]
+
+        self.client = ApiClient(config)
+
     def send(self, messages):
         messages = messages[:MAX_BATCH_SIZE]
 
         try:
-            response = SMSApi(client).sms_send_post(
+            response = SMSApi(self.client).sms_send_post(
                 SmsMessageCollection(
                     messages=[
                         SmsMessage(
diff --git a/shiftregister/messaging/backends/sipgate.py b/shiftregister/messaging/backends/sipgate.py
index 57b66fa..9dee189 100644
--- a/shiftregister/messaging/backends/sipgate.py
+++ b/shiftregister/messaging/backends/sipgate.py
@@ -12,22 +12,18 @@ __all__ = ("Receiver", "Sender")
 
 BASE_URL = "https://api.sipgate.com/v2"
 
-inbound_auth = HTTPBasicAuth(
-    settings.SMS_SETTINGS.get(
-        "sipgate_incoming_token_id", settings.SIPGATE_INCOMING_TOKEN_ID
-    ),
-    settings.SMS_SETTINGS.get(
-        "sipgate_incoming_token", settings.SIPGATE_INCOMING_TOKEN
-    ),
-)
-outbound_auth = HTTPBasicAuth(
-    settings.SMS_SETTINGS.get("sipgate_token_id", settings.SIPGATE_TOKEN_ID),
-    settings.SMS_SETTINGS.get("sipgate_token", settings.SIPGATE_TOKEN),
-)
-
 
 class Receiver(BaseReceiver):
     def __init__(self):
+        self.auth = HTTPBasicAuth(
+            settings.SMS_SETTINGS.get(
+                "sipgate_incoming_token_id", settings.SIPGATE_INCOMING_TOKEN_ID
+            ),
+            settings.SMS_SETTINGS.get(
+                "sipgate_incoming_token", settings.SIPGATE_INCOMING_TOKEN
+            ),
+        )
+
         self.from_dt = None
 
     def fetch(self):
@@ -50,7 +46,7 @@ class Receiver(BaseReceiver):
         while offset < total:
             r = requests.get(
                 f"{BASE_URL}/history",
-                auth=inbound_auth,
+                auth=self.auth,
                 params=params | {"offset": offset},
             )
             r.raise_for_status()
@@ -75,11 +71,17 @@ class Receiver(BaseReceiver):
 
 
 class Sender(BaseSender):
+    def __init__(self):
+        self.auth = HTTPBasicAuth(
+            settings.SMS_SETTINGS.get("sipgate_token_id", settings.SIPGATE_TOKEN_ID),
+            settings.SMS_SETTINGS.get("sipgate_token", settings.SIPGATE_TOKEN),
+        )
+
     def send(self, messages):
         for message in messages:
             r = requests.post(
                 f"{BASE_URL}/sessions/sms",
-                auth=outbound_auth,
+                auth=self.auth,
                 json={
                     "smsId": settings.SMS_SETTINGS.get(
                         "sipgate_sms_extension", settings.SIPGATE_SMS_EXTENSION