diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index 7e1718d4..f318350f 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -7,6 +7,8 @@ env:
   PROJECT_ID: ${{ secrets.PROJECT_ID }}
   NUMBERS_ORIGIN: ${{ secrets.NUMBERS_ORIGIN }}
   SMS_ORIGIN: ${{ secrets.SMS_ORIGIN }}
+  SERVICE_PLAN_ID: ${{ secrets.SERVICE_PLAN_ID }}
+  SMS_API_TOKEN: ${{ secrets.SMS_API_TOKEN }}
   CONVERSATION_ORIGIN: ${{ secrets.CONVERSATION_ORIGIN }}
   AUTH_ORIGIN: ${{ secrets.AUTH_ORIGIN }}
   DISABLE_SSL: ${{ secrets.DISABLE_SSL }}
diff --git a/sinch/core/clients/sinch_client_async.py b/sinch/core/clients/sinch_client_async.py
index 72f34593..55133dc7 100644
--- a/sinch/core/clients/sinch_client_async.py
+++ b/sinch/core/clients/sinch_client_async.py
@@ -25,7 +25,9 @@ def __init__(
         logger_name: str = None,
         logger: Logger = None,
         application_key: str = None,
-        application_secret: str = None
+        application_secret: str = None,
+        service_plan_id: str = None,
+        sms_api_token: str = None
     ):
         self.configuration = Configuration(
             key_id=key_id,
@@ -36,7 +38,9 @@ def __init__(
             transport=HTTPXTransport(self),
             token_manager=TokenManagerAsync(self),
             application_secret=application_secret,
-            application_key=application_key
+            application_key=application_key,
+            service_plan_id=service_plan_id,
+            sms_api_token=sms_api_token
         )
 
         self.authentication = AuthenticationAsync(self)
diff --git a/sinch/core/clients/sinch_client_base.py b/sinch/core/clients/sinch_client_base.py
index f7f66c91..6072bfe0 100644
--- a/sinch/core/clients/sinch_client_base.py
+++ b/sinch/core/clients/sinch_client_base.py
@@ -30,7 +30,9 @@ def __init__(
         logger_name: str = None,
         logger: Logger = None,
         application_key: str = None,
-        application_secret: str = None
+        application_secret: str = None,
+        service_plan_id: str = None,
+        sms_api_token: str = None
     ):
         pass
 
diff --git a/sinch/core/clients/sinch_client_configuration.py b/sinch/core/clients/sinch_client_configuration.py
index 7ec0ec91..1af0f756 100644
--- a/sinch/core/clients/sinch_client_configuration.py
+++ b/sinch/core/clients/sinch_client_configuration.py
@@ -4,6 +4,7 @@
 
 from sinch.core.ports.http_transport import HTTPTransport
 from sinch.core.token_manager import TokenManager, TokenManagerAsync
+from sinch.core.enums import HTTPAuthentication
 
 
 class Configuration:
@@ -22,7 +23,9 @@ def __init__(
         disable_https=False,
         connection_timeout=10,
         application_key: str = None,
-        application_secret: str = None
+        application_secret: str = None,
+        service_plan_id: str = None,
+        sms_api_token: str = None
     ):
         self.key_id = key_id
         self.key_secret = key_secret
@@ -30,6 +33,8 @@ def __init__(
         self.application_key = application_key
         self.application_secret = application_secret
         self.connection_timeout = connection_timeout
+        self.sms_api_token = sms_api_token
+        self.service_plan_id = service_plan_id
         self.auth_origin = "auth.sinch.com"
         self.numbers_origin = "numbers.api.sinch.com"
         self.verification_origin = "verification.api.sinch.com"
@@ -39,7 +44,10 @@ def __init__(
         self._conversation_region = "eu"
         self._conversation_domain = ".conversation.api.sinch.com"
         self._sms_region = "us"
+        self._sms_region_with_service_plan_id = "us"
         self._sms_domain = "zt.{}.sms.api.sinch.com"
+        self._sms_domain_with_service_plan_id = "{}.sms.api.sinch.com"
+        self._sms_authentication = HTTPAuthentication.OAUTH.value
         self._templates_region = "eu"
         self._templates_domain = ".template.api.sinch.com"
         self.token_manager = token_manager
@@ -48,6 +56,7 @@ def __init__(
 
         self._set_conversation_origin()
         self._set_sms_origin()
+        self._set_sms_origin_with_service_plan_id()
         self._set_templates_origin()
         self._set_voice_origin()
 
@@ -58,23 +67,35 @@ def __init__(
         else:
             self.logger = logging.getLogger("Sinch")
 
-    def _set_voice_origin(self):
-        if not self._voice_region:
-            self.voice_origin = self._voice_domain.format("calling")
-        else:
-            self.voice_origin = self._voice_domain.format("calling-" + self._voice_region)
+    def _set_sms_origin_with_service_plan_id(self):
+        self.sms_origin_with_service_plan_id = self._sms_domain_with_service_plan_id.format(
+            self._sms_region_with_service_plan_id
+        )
 
-    def _set_voice_region(self, region):
-        self._voice_region = region
-        self._set_voice_origin()
+    def _set_sms_region_with_service_plan_id(self, region):
+        self._sms_region_with_service_plan_id = region
+        self._set_sms_origin_with_service_plan_id()
 
-    def _get_voice_region(self):
-        return self._voice_region
+    def _get_sms_region_with_service_plan_id(self):
+        return self._sms_region_with_service_plan_id
 
-    voice_region = property(
-        _get_voice_region,
-        _set_voice_region,
-        doc="Voice Region"
+    sms_region_with_service_plan_id = property(
+        _get_sms_region_with_service_plan_id,
+        _set_sms_region_with_service_plan_id,
+        doc="SMS Region for service plan id version of the SMS API"
+    )
+
+    def _set_sms_domain_with_service_plan_id(self, domain):
+        self._sms_domain_with_service_plan_id = domain
+        self._set_sms_origin_with_service_plan_id()
+
+    def _get_sms_domain_with_service_plan_id(self):
+        return self._sms_domain_with_service_plan_id
+
+    sms_domain_with_service_plan_id = property(
+        _get_sms_domain_with_service_plan_id,
+        _set_sms_domain_with_service_plan_id,
+        doc="SMS Domain for service plan id version of the SMS API"
     )
 
     def _set_sms_origin(self):
@@ -163,3 +184,22 @@ def _get_templates_domain(self):
         _set_templates_domain,
         doc="Conversation API Templates Domain"
     )
+
+    def _set_voice_origin(self):
+        if not self._voice_region:
+            self.voice_origin = self._voice_domain.format("calling")
+        else:
+            self.voice_origin = self._voice_domain.format("calling-" + self._voice_region)
+
+    def _set_voice_region(self, region):
+        self._voice_region = region
+        self._set_voice_origin()
+
+    def _get_voice_region(self):
+        return self._voice_region
+
+    voice_region = property(
+        _get_voice_region,
+        _set_voice_region,
+        doc="Voice Region"
+    )
diff --git a/sinch/core/clients/sinch_client_sync.py b/sinch/core/clients/sinch_client_sync.py
index 45f249a1..b2e6055c 100644
--- a/sinch/core/clients/sinch_client_sync.py
+++ b/sinch/core/clients/sinch_client_sync.py
@@ -25,7 +25,9 @@ def __init__(
         logger_name: str = None,
         logger: Logger = None,
         application_key: str = None,
-        application_secret: str = None
+        application_secret: str = None,
+        service_plan_id: str = None,
+        sms_api_token: str = None
     ):
         self.configuration = Configuration(
             key_id=key_id,
@@ -36,7 +38,9 @@ def __init__(
             transport=HTTPTransportRequests(self),
             token_manager=TokenManager(self),
             application_key=application_key,
-            application_secret=application_secret
+            application_secret=application_secret,
+            service_plan_id=service_plan_id,
+            sms_api_token=sms_api_token
         )
 
         self.authentication = Authentication(self)
diff --git a/sinch/core/enums.py b/sinch/core/enums.py
index c1d63ee8..0898c2cc 100644
--- a/sinch/core/enums.py
+++ b/sinch/core/enums.py
@@ -13,3 +13,4 @@ class HTTPAuthentication(Enum):
     BASIC = "BASIC"
     OAUTH = "OAUTH"
     SIGNED = "SIGNED"
+    SMS_TOKEN = "SMS_TOKEN"
diff --git a/sinch/core/ports/http_transport.py b/sinch/core/ports/http_transport.py
index 865ea719..e76f38b9 100644
--- a/sinch/core/ports/http_transport.py
+++ b/sinch/core/ports/http_transport.py
@@ -63,6 +63,20 @@ def authenticate(self, endpoint, request_data):
                 endpoint.get_url_without_origin(self.sinch)
             )
             request_data.headers = signature.get_http_headers_with_signature()
+        elif endpoint.HTTP_AUTHENTICATION == HTTPAuthentication.SMS_TOKEN.value:
+            if not self.sinch.configuration.sms_api_token or not self.sinch.configuration.service_plan_id:
+                raise ValidationException(
+                    message=(
+                        "sms_api_token and service_plan_id are required by this API. "
+                        "Those credentials can be obtained from Sinch portal."
+                    ),
+                    is_from_server=False,
+                    response=None
+                )
+            request_data.headers.update({
+                "Authorization": f"Bearer {self.sinch.configuration.sms_api_token}",
+                "Content-Type": "application/json"
+            })
 
         return request_data
 
diff --git a/sinch/domains/sms/__init__.py b/sinch/domains/sms/__init__.py
index ac3a39e0..d2223066 100644
--- a/sinch/domains/sms/__init__.py
+++ b/sinch/domains/sms/__init__.py
@@ -111,7 +111,7 @@ def list(
         return IntBasedPaginator._initialize(
             sinch=self._sinch,
             endpoint=ListDeliveryReportsEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=ListSMSDeliveryReportsRequest(
                     page=page,
                     page_size=page_size,
@@ -133,7 +133,7 @@ def get_for_batch(
     ) -> GetSMSDeliveryReportForBatchResponse:
         return self._sinch.configuration.transport.request(
             GetDeliveryReportForBatchEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=GetSMSDeliveryReportForBatchRequest(
                     batch_id=batch_id,
                     type_=type_,
@@ -150,7 +150,7 @@ def get_for_number(
     ) -> GetSMSDeliveryReportForNumberResponse:
         return self._sinch.configuration.transport.request(
             GetDeliveryReportForNumberEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=GetSMSDeliveryReportForNumberRequest(
                     batch_id=batch_id,
                     recipient_number=recipient_number
@@ -173,7 +173,7 @@ async def list(
         return await AsyncIntBasedPaginator._initialize(
             sinch=self._sinch,
             endpoint=ListDeliveryReportsEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=ListSMSDeliveryReportsRequest(
                     page=page,
                     page_size=page_size,
@@ -203,7 +203,7 @@ def list(
         return IntBasedPaginator._initialize(
             sinch=self._sinch,
             endpoint=ListInboundMessagesEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=ListSMSInboundMessageRequest(
                     page=page,
                     page_size=page_size,
@@ -218,7 +218,7 @@ def list(
     def get(self, inbound_id: str) -> GetInboundMessagesResponse:
         return self._sinch.configuration.transport.request(
             GetInboundMessagesEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=GetSMSInboundMessageRequest(
                     inbound_id=inbound_id
                 )
@@ -239,7 +239,7 @@ async def list(
         return await AsyncIntBasedPaginator._initialize(
             sinch=self._sinch,
             endpoint=ListInboundMessagesEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=ListSMSInboundMessageRequest(
                     page=page,
                     page_size=page_size,
@@ -277,7 +277,7 @@ def send(
     ) -> SendSMSBatchResponse:
         return self._sinch.configuration.transport.request(
             SendBatchSMSEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=SendBatchRequest(
                     to=to,
                     body=body,
@@ -311,7 +311,7 @@ def list(
         return IntBasedPaginator._initialize(
             sinch=self._sinch,
             endpoint=ListSMSBatchesEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=ListBatchesRequest(
                     page=page,
                     page_size=page_size,
@@ -326,7 +326,7 @@ def list(
     def get(self, batch_id: str) -> GetSMSBatchResponse:
         return self._sinch.configuration.transport.request(
             GetSMSEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=GetBatchRequest(
                     batch_id=batch_id
                 )
@@ -353,7 +353,7 @@ def send_dry_run(
     ) -> SendSMSBatchDryRunResponse:
         return self._sinch.configuration.transport.request(
             SendBatchSMSDryRunEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=BatchDryRunRequest(
                     per_recipient=per_recipient,
                     number_of_recipients=number_of_recipients,
@@ -377,7 +377,7 @@ def send_dry_run(
     def cancel(self, batch_id: str) -> CancelSMSBatchResponse:
         return self._sinch.configuration.transport.request(
             CancelBatchEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=CancelBatchRequest(
                     batch_id=batch_id
                 )
@@ -398,7 +398,7 @@ def update(
     ) -> UpdateSMSBatchResponse:
         return self._sinch.configuration.transport.request(
             UpdateBatchSMSEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=UpdateBatchRequest(
                     batch_id=batch_id,
                     to_add=to_add,
@@ -432,7 +432,7 @@ def replace(
     ) -> ReplaceSMSBatchResponse:
         return self._sinch.configuration.transport.request(
             ReplaceBatchSMSEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=ReplaceBatchRequest(
                     batch_id=batch_id,
                     to=to,
@@ -459,7 +459,7 @@ def send_delivery_feedback(
     ) -> SendSMSDeliveryFeedbackResponse:
         return self._sinch.configuration.transport.request(
             SendDeliveryReportEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=SendDeliveryFeedbackRequest(
                     batch_id=batch_id,
                     recipients=recipients
@@ -481,7 +481,7 @@ async def list(
         return await AsyncIntBasedPaginator._initialize(
             sinch=self._sinch,
             endpoint=ListSMSBatchesEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=ListBatchesRequest(
                     page=page,
                     page_size=page_size,
@@ -507,7 +507,7 @@ def create(
     ) -> CreateSMSGroupResponse:
         return self._sinch.configuration.transport.request(
             CreateSMSGroupEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=CreateSMSGroupRequest(
                     name=name,
                     members=members,
@@ -525,7 +525,7 @@ def list(
         return IntBasedPaginator._initialize(
             sinch=self._sinch,
             endpoint=ListSMSGroupEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=ListSMSGroupRequest(
                     page=page,
                     page_size=page_size
@@ -539,7 +539,7 @@ def delete(
     ) -> SinchDeleteSMSGroupResponse:
         return self._sinch.configuration.transport.request(
             DeleteSMSGroupEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=DeleteSMSGroupRequest(
                     group_id=group_id
                 )
@@ -552,7 +552,7 @@ def get(
     ) -> GetSMSGroupResponse:
         return self._sinch.configuration.transport.request(
             GetSMSGroupEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=GetSMSGroupRequest(
                     group_id=group_id
                 )
@@ -565,7 +565,7 @@ def get_group_phone_numbers(
     ) -> SinchGetSMSGroupPhoneNumbersResponse:
         return self._sinch.configuration.transport.request(
             GetSMSGroupPhoneNumbersEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=GetSMSGroupPhoneNumbersRequest(
                     group_id=group_id
                 )
@@ -584,7 +584,7 @@ def update(
     ) -> UpdateSMSGroupResponse:
         return self._sinch.configuration.transport.request(
             UpdateSMSGroupEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=UpdateSMSGroupRequest(
                     group_id=group_id,
                     name=name,
@@ -605,7 +605,7 @@ def replace(
     ) -> ReplaceSMSGroupResponse:
         return self._sinch.configuration.transport.request(
             ReplaceSMSGroupEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=ReplaceSMSGroupPhoneNumbersRequest(
                     group_id=group_id,
                     members=members,
@@ -624,7 +624,7 @@ async def list(
         return await AsyncIntBasedPaginator._initialize(
             sinch=self._sinch,
             endpoint=ListSMSGroupEndpoint(
-                project_id=self._sinch.configuration.project_id,
+                sinch=self._sinch,
                 request_data=ListSMSGroupRequest(
                     page=page,
                     page_size=page_size
diff --git a/sinch/domains/sms/endpoints/batches/cancel_batch.py b/sinch/domains/sms/endpoints/batches/cancel_batch.py
index 757fa29f..091a966d 100644
--- a/sinch/domains/sms/endpoints/batches/cancel_batch.py
+++ b/sinch/domains/sms/endpoints/batches/cancel_batch.py
@@ -6,19 +6,17 @@
 
 
 class CancelBatchEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/batches/{batch_id}"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/batches/{batch_id}"
     HTTP_METHOD = HTTPMethods.DELETE.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: CancelBatchRequest):
-        super(CancelBatchEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: CancelBatchRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
-            origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            origin=self.sms_origin,
+            project_or_service_id=self.project_or_service_id,
             batch_id=self.request_data.batch_id
         )
 
diff --git a/sinch/domains/sms/endpoints/batches/get_batch.py b/sinch/domains/sms/endpoints/batches/get_batch.py
index 70a6a7c8..555ab5d6 100644
--- a/sinch/domains/sms/endpoints/batches/get_batch.py
+++ b/sinch/domains/sms/endpoints/batches/get_batch.py
@@ -6,19 +6,17 @@
 
 
 class GetSMSEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/batches/{batch_id}"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/batches/{batch_id}"
     HTTP_METHOD = HTTPMethods.GET.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: GetBatchRequest):
-        super(GetSMSEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: GetBatchRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
-            origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            origin=self.sms_origin,
+            project_or_service_id=self.project_or_service_id,
             batch_id=self.request_data.batch_id
         )
 
diff --git a/sinch/domains/sms/endpoints/batches/list_batches.py b/sinch/domains/sms/endpoints/batches/list_batches.py
index 65625dba..b770efbf 100644
--- a/sinch/domains/sms/endpoints/batches/list_batches.py
+++ b/sinch/domains/sms/endpoints/batches/list_batches.py
@@ -7,19 +7,17 @@
 
 
 class ListSMSBatchesEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/batches"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/batches"
     HTTP_METHOD = HTTPMethods.GET.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: ListBatchesRequest):
-        super(ListSMSBatchesEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: ListBatchesRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
-            origin=sinch.configuration.sms_origin,
-            project_id=self.project_id
+            origin=self.sms_origin,
+            project_or_service_id=self.project_or_service_id
         )
 
     def build_query_params(self):
diff --git a/sinch/domains/sms/endpoints/batches/replace_batch.py b/sinch/domains/sms/endpoints/batches/replace_batch.py
index fdc20387..15fdd838 100644
--- a/sinch/domains/sms/endpoints/batches/replace_batch.py
+++ b/sinch/domains/sms/endpoints/batches/replace_batch.py
@@ -6,19 +6,17 @@
 
 
 class ReplaceBatchSMSEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/batches/{batch_id}"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/batches/{batch_id}"
     HTTP_METHOD = HTTPMethods.PUT.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: ReplaceBatchRequest):
-        super(ReplaceBatchSMSEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: ReplaceBatchRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
-            origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            origin=self.sms_origin,
+            project_or_service_id=self.project_or_service_id,
             batch_id=self.request_data.batch_id
         )
 
diff --git a/sinch/domains/sms/endpoints/batches/send_batch.py b/sinch/domains/sms/endpoints/batches/send_batch.py
index 249a4ebc..4bb94f1a 100644
--- a/sinch/domains/sms/endpoints/batches/send_batch.py
+++ b/sinch/domains/sms/endpoints/batches/send_batch.py
@@ -6,19 +6,17 @@
 
 
 class SendBatchSMSEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/batches"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/batches"
     HTTP_METHOD = HTTPMethods.POST.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: SendBatchRequest):
-        super(SendBatchSMSEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: SendBatchRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
-            origin=sinch.configuration.sms_origin,
-            project_id=self.project_id
+            origin=self.sms_origin,
+            project_or_service_id=self.project_or_service_id
         )
 
     def request_body(self):
diff --git a/sinch/domains/sms/endpoints/batches/send_batch_dry_run.py b/sinch/domains/sms/endpoints/batches/send_batch_dry_run.py
index 7cddf4d0..b9c64f2a 100644
--- a/sinch/domains/sms/endpoints/batches/send_batch_dry_run.py
+++ b/sinch/domains/sms/endpoints/batches/send_batch_dry_run.py
@@ -6,19 +6,17 @@
 
 
 class SendBatchSMSDryRunEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/batches/dry_run"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/batches/dry_run"
     HTTP_METHOD = HTTPMethods.POST.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: BatchDryRunRequest):
-        super(SendBatchSMSDryRunEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: BatchDryRunRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id
+            project_or_service_id=self.project_or_service_id
         )
 
     def build_query_params(self):
diff --git a/sinch/domains/sms/endpoints/batches/send_delivery_feedback.py b/sinch/domains/sms/endpoints/batches/send_delivery_feedback.py
index 2eb2b3cf..3c3f7933 100644
--- a/sinch/domains/sms/endpoints/batches/send_delivery_feedback.py
+++ b/sinch/domains/sms/endpoints/batches/send_delivery_feedback.py
@@ -6,19 +6,17 @@
 
 
 class SendDeliveryReportEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/batches/{batch_id}/delivery_feedback"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/batches/{batch_id}/delivery_feedback"
     HTTP_METHOD = HTTPMethods.POST.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: SendDeliveryFeedbackRequest):
-        super(SendDeliveryReportEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: SendDeliveryFeedbackRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            project_or_service_id=self.project_or_service_id,
             batch_id=self.request_data.batch_id
         )
 
diff --git a/sinch/domains/sms/endpoints/batches/update_batch.py b/sinch/domains/sms/endpoints/batches/update_batch.py
index e9e02c83..28a88056 100644
--- a/sinch/domains/sms/endpoints/batches/update_batch.py
+++ b/sinch/domains/sms/endpoints/batches/update_batch.py
@@ -6,19 +6,17 @@
 
 
 class UpdateBatchSMSEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/batches/{batch_id}"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/batches/{batch_id}"
     HTTP_METHOD = HTTPMethods.POST.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: UpdateBatchRequest):
-        super(UpdateBatchSMSEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: UpdateBatchRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            project_or_service_id=self.project_or_service_id,
             batch_id=self.request_data.batch_id
         )
 
diff --git a/sinch/domains/sms/endpoints/delivery_reports/get_all_delivery_reports_for_project.py b/sinch/domains/sms/endpoints/delivery_reports/get_all_delivery_reports_for_project.py
index 65b8c869..dc1b55d8 100644
--- a/sinch/domains/sms/endpoints/delivery_reports/get_all_delivery_reports_for_project.py
+++ b/sinch/domains/sms/endpoints/delivery_reports/get_all_delivery_reports_for_project.py
@@ -7,19 +7,17 @@
 
 
 class ListDeliveryReportsEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/delivery_reports"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/delivery_reports"
     HTTP_METHOD = HTTPMethods.GET.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: ListSMSDeliveryReportsRequest):
-        super(ListDeliveryReportsEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: ListSMSDeliveryReportsRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id
+            project_or_service_id=self.project_or_service_id
         )
 
     def build_query_params(self):
diff --git a/sinch/domains/sms/endpoints/delivery_reports/get_delivery_report_for_batch.py b/sinch/domains/sms/endpoints/delivery_reports/get_delivery_report_for_batch.py
index aa25bb87..4018d3bf 100644
--- a/sinch/domains/sms/endpoints/delivery_reports/get_delivery_report_for_batch.py
+++ b/sinch/domains/sms/endpoints/delivery_reports/get_delivery_report_for_batch.py
@@ -6,14 +6,12 @@
 
 
 class GetDeliveryReportForBatchEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/batches/{batch_id}/delivery_report"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/batches/{batch_id}/delivery_report"
     HTTP_METHOD = HTTPMethods.GET.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: GetSMSDeliveryReportForBatchRequest):
-        super(GetDeliveryReportForBatchEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: GetSMSDeliveryReportForBatchRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_query_params(self):
         params = {}
@@ -31,7 +29,7 @@ def build_query_params(self):
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            project_or_service_id=self.project_or_service_id,
             batch_id=self.request_data.batch_id
         )
 
diff --git a/sinch/domains/sms/endpoints/delivery_reports/get_delivery_report_for_number.py b/sinch/domains/sms/endpoints/delivery_reports/get_delivery_report_for_number.py
index 8cc737eb..97dcdf9d 100644
--- a/sinch/domains/sms/endpoints/delivery_reports/get_delivery_report_for_number.py
+++ b/sinch/domains/sms/endpoints/delivery_reports/get_delivery_report_for_number.py
@@ -6,19 +6,17 @@
 
 
 class GetDeliveryReportForNumberEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/batches/{batch_id}/delivery_report/{recipient_msisdn}"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/batches/{batch_id}/delivery_report/{recipient_msisdn}"
     HTTP_METHOD = HTTPMethods.GET.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: GetSMSDeliveryReportForNumberRequest):
-        super(GetDeliveryReportForNumberEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: GetSMSDeliveryReportForNumberRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            project_or_service_id=self.project_or_service_id,
             batch_id=self.request_data.batch_id,
             recipient_msisdn=self.request_data.recipient_number
         )
diff --git a/sinch/domains/sms/endpoints/groups/create_group.py b/sinch/domains/sms/endpoints/groups/create_group.py
index d384d9b4..3d57eb91 100644
--- a/sinch/domains/sms/endpoints/groups/create_group.py
+++ b/sinch/domains/sms/endpoints/groups/create_group.py
@@ -6,19 +6,17 @@
 
 
 class CreateSMSGroupEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/groups"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/groups"
     HTTP_METHOD = HTTPMethods.POST.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: CreateSMSGroupRequest):
-        super(CreateSMSGroupEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: CreateSMSGroupRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id
+            project_or_service_id=self.project_or_service_id
         )
 
     def request_body(self):
diff --git a/sinch/domains/sms/endpoints/groups/delete_group.py b/sinch/domains/sms/endpoints/groups/delete_group.py
index afaaa62b..e4790c3c 100644
--- a/sinch/domains/sms/endpoints/groups/delete_group.py
+++ b/sinch/domains/sms/endpoints/groups/delete_group.py
@@ -6,19 +6,17 @@
 
 
 class DeleteSMSGroupEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/groups/{group_id}"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/groups/{group_id}"
     HTTP_METHOD = HTTPMethods.DELETE.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: DeleteSMSGroupRequest):
-        super(DeleteSMSGroupEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: DeleteSMSGroupRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            project_or_service_id=self.project_or_service_id,
             group_id=self.request_data.group_id
         )
 
diff --git a/sinch/domains/sms/endpoints/groups/get_group.py b/sinch/domains/sms/endpoints/groups/get_group.py
index 7e14f82b..23c98848 100644
--- a/sinch/domains/sms/endpoints/groups/get_group.py
+++ b/sinch/domains/sms/endpoints/groups/get_group.py
@@ -6,19 +6,17 @@
 
 
 class GetSMSGroupEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/groups/{group_id}"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/groups/{group_id}"
     HTTP_METHOD = HTTPMethods.GET.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: GetSMSGroupRequest):
-        super(GetSMSGroupEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: GetSMSGroupRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            project_or_service_id=self.project_or_service_id,
             group_id=self.request_data.group_id
         )
 
diff --git a/sinch/domains/sms/endpoints/groups/get_phone_numbers_for_group.py b/sinch/domains/sms/endpoints/groups/get_phone_numbers_for_group.py
index 1e203f6f..7e1e81ac 100644
--- a/sinch/domains/sms/endpoints/groups/get_phone_numbers_for_group.py
+++ b/sinch/domains/sms/endpoints/groups/get_phone_numbers_for_group.py
@@ -6,19 +6,17 @@
 
 
 class GetSMSGroupPhoneNumbersEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/groups/{group_id}/members"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/groups/{group_id}/members"
     HTTP_METHOD = HTTPMethods.GET.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: GetSMSGroupPhoneNumbersRequest):
-        super(GetSMSGroupPhoneNumbersEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: GetSMSGroupPhoneNumbersRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            project_or_service_id=self.project_or_service_id,
             group_id=self.request_data.group_id
         )
 
diff --git a/sinch/domains/sms/endpoints/groups/list_groups.py b/sinch/domains/sms/endpoints/groups/list_groups.py
index a25460be..758f3f71 100644
--- a/sinch/domains/sms/endpoints/groups/list_groups.py
+++ b/sinch/domains/sms/endpoints/groups/list_groups.py
@@ -7,19 +7,17 @@
 
 
 class ListSMSGroupEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/groups"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/groups"
     HTTP_METHOD = HTTPMethods.GET.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: ListSMSGroupRequest):
-        super(ListSMSGroupEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: ListSMSGroupRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id
+            project_or_service_id=self.project_or_service_id
         )
 
     def build_query_params(self):
diff --git a/sinch/domains/sms/endpoints/groups/replace_group.py b/sinch/domains/sms/endpoints/groups/replace_group.py
index 1db394c5..07234168 100644
--- a/sinch/domains/sms/endpoints/groups/replace_group.py
+++ b/sinch/domains/sms/endpoints/groups/replace_group.py
@@ -6,19 +6,17 @@
 
 
 class ReplaceSMSGroupEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/groups/{group_id}"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/groups/{group_id}"
     HTTP_METHOD = HTTPMethods.PUT.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: ReplaceSMSGroupPhoneNumbersRequest):
-        super(ReplaceSMSGroupEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: ReplaceSMSGroupPhoneNumbersRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            project_or_service_id=self.project_or_service_id,
             group_id=self.request_data.group_id
         )
 
diff --git a/sinch/domains/sms/endpoints/groups/update_group.py b/sinch/domains/sms/endpoints/groups/update_group.py
index eb834048..ccc4d0c2 100644
--- a/sinch/domains/sms/endpoints/groups/update_group.py
+++ b/sinch/domains/sms/endpoints/groups/update_group.py
@@ -6,19 +6,17 @@
 
 
 class UpdateSMSGroupEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/groups/{group_id}"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/groups/{group_id}"
     HTTP_METHOD = HTTPMethods.POST.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: UpdateSMSGroupRequest):
-        super(UpdateSMSGroupEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: UpdateSMSGroupRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            project_or_service_id=self.project_or_service_id,
             group_id=self.request_data.group_id
         )
 
diff --git a/sinch/domains/sms/endpoints/inbounds/get_incoming_message.py b/sinch/domains/sms/endpoints/inbounds/get_incoming_message.py
index 9cfb371f..94f7d052 100644
--- a/sinch/domains/sms/endpoints/inbounds/get_incoming_message.py
+++ b/sinch/domains/sms/endpoints/inbounds/get_incoming_message.py
@@ -6,19 +6,17 @@
 
 
 class GetInboundMessagesEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/inbounds/{inbound_id}"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/inbounds/{inbound_id}"
     HTTP_METHOD = HTTPMethods.GET.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: GetSMSInboundMessageRequest):
-        super(GetInboundMessagesEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: GetSMSInboundMessageRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id,
+            project_or_service_id=self.project_or_service_id,
             inbound_id=self.request_data.inbound_id
         )
 
diff --git a/sinch/domains/sms/endpoints/inbounds/list_incoming_messages.py b/sinch/domains/sms/endpoints/inbounds/list_incoming_messages.py
index 327f1578..4eb2d2d4 100644
--- a/sinch/domains/sms/endpoints/inbounds/list_incoming_messages.py
+++ b/sinch/domains/sms/endpoints/inbounds/list_incoming_messages.py
@@ -7,19 +7,17 @@
 
 
 class ListInboundMessagesEndpoint(SMSEndpoint):
-    ENDPOINT_URL = "{origin}/xms/v1/{project_id}/inbounds"
+    ENDPOINT_URL = "{origin}/xms/v1/{project_or_service_id}/inbounds"
     HTTP_METHOD = HTTPMethods.GET.value
     HTTP_AUTHENTICATION = HTTPAuthentication.OAUTH.value
 
-    def __init__(self, project_id: str, request_data: ListSMSInboundMessageRequest):
-        super(ListInboundMessagesEndpoint, self).__init__(project_id, request_data)
-        self.project_id = project_id
-        self.request_data = request_data
+    def __init__(self, request_data: ListSMSInboundMessageRequest, sinch):
+        super().__init__(request_data, sinch)
 
     def build_url(self, sinch) -> str:
         return self.ENDPOINT_URL.format(
             origin=sinch.configuration.sms_origin,
-            project_id=self.project_id
+            project_or_service_id=self.project_or_service_id
         )
 
     def build_query_params(self):
diff --git a/sinch/domains/sms/endpoints/sms_endpoint.py b/sinch/domains/sms/endpoints/sms_endpoint.py
index ba82ae2b..89bcb830 100644
--- a/sinch/domains/sms/endpoints/sms_endpoint.py
+++ b/sinch/domains/sms/endpoints/sms_endpoint.py
@@ -1,9 +1,23 @@
 from sinch.core.models.http_response import HTTPResponse
 from sinch.core.endpoint import HTTPEndpoint
 from sinch.domains.sms.exceptions import SMSException
+from sinch.core.enums import HTTPAuthentication
 
 
 class SMSEndpoint(HTTPEndpoint):
+    def __init__(self, request_data, sinch):
+        self.request_data = request_data
+        self.sinch = sinch
+
+        if sinch.configuration.service_plan_id:
+            self.project_or_service_id = sinch.configuration.service_plan_id
+            self.HTTP_AUTHENTICATION = HTTPAuthentication.SMS_TOKEN.value
+            self.sms_origin = self.sinch.configuration.sms_origin_with_service_plan_id
+
+        else:
+            self.project_or_service_id = sinch.configuration.project_id
+            self.sms_origin = self.sinch.configuration.sms_origin
+
     def handle_response(self, response: HTTPResponse):
         if response.status_code >= 400:
             raise SMSException(
diff --git a/tests/conftest.py b/tests/conftest.py
index 6fb297b7..a6625f5d 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -5,6 +5,7 @@
 from sinch import SinchClient
 from sinch import SinchClientAsync
 from sinch.core.models.http_response import HTTPResponse
+from sinch.core.models.http_request import HttpRequest
 from sinch.domains.authentication.models.authentication import OAuthToken
 from sinch.core.models.base_model import SinchBaseModel, SinchRequestBaseModel
 
@@ -60,6 +61,7 @@ def configure_origin(
 
     if sms_origin:
         sinch_client.configuration.sms_origin = sms_origin
+        sinch_client.configuration.sms_origin_with_service_plan_id = sms_origin
 
     if verification_origin:
         sinch_client.configuration.verification_origin = verification_origin
@@ -154,6 +156,16 @@ def application_secret():
     return os.getenv("APPLICATION_SECRET")
 
 
+@pytest.fixture
+def service_plan_id():
+    return os.getenv("SERVICE_PLAN_ID")
+
+
+@pytest.fixture
+def sms_api_token():
+    return os.getenv("SMS_API_TOKEN")
+
+
 @pytest.fixture
 def verification_id():
     return os.getenv("VERIFICATION_ID")
@@ -204,6 +216,19 @@ def verification_request_signature_timestamp():
     return os.getenv("VERIFICATION_REQUEST_SIGNATURE_TIMESTAMP")
 
 
+@pytest.fixture
+def empty_http_request():
+    return HttpRequest(
+        headers={},
+        protocol=None,
+        http_method=None,
+        request_body=None,
+        query_params=None,
+        url=None,
+        auth=None
+    )
+
+
 @pytest.fixture
 def http_response():
     return HTTPResponse(
@@ -286,6 +311,14 @@ def second_token_based_pagination_response():
     )
 
 
+@pytest.fixture
+def int_based_pagination_request_data():
+    return IntBasedPaginationRequest(
+        page=0,
+        page_size=2
+    )
+
+
 @pytest.fixture
 def first_int_based_pagination_response():
     return IntBasedPaginationResponse(
@@ -316,14 +349,6 @@ def third_int_based_pagination_response():
     )
 
 
-@pytest.fixture
-def int_based_pagination_request_data():
-    return IntBasedPaginationRequest(
-        page=0,
-        page_size=2
-    )
-
-
 @pytest.fixture
 def sinch_client_sync(
     key_id,
@@ -392,3 +417,14 @@ def sinch_client_async(
         voice_origin,
         disable_ssl
     )
+
+
+@pytest.fixture
+def sinch_client_sync_with_service_plan_id(
+    sinch_client_sync,
+    service_plan_id,
+    sms_api_token
+):
+    sinch_client_sync.configuration.service_plan_id = service_plan_id
+    sinch_client_sync.configuration.sms_api_token = sms_api_token
+    return sinch_client_sync
diff --git a/tests/e2e/conversation/contact/test_merge_contacts.py b/tests/e2e/conversation/contact/test_merge_contacts.py
index be1d1891..bf1279ef 100644
--- a/tests/e2e/conversation/contact/test_merge_contacts.py
+++ b/tests/e2e/conversation/contact/test_merge_contacts.py
@@ -1,4 +1,7 @@
-from sinch.domains.conversation.models.contact.responses import MergeConversationContactsResponse, ListConversationContactsResponse
+from sinch.domains.conversation.models.contact.responses import (
+    MergeConversationContactsResponse,
+    ListConversationContactsResponse
+)
 
 
 def test_merge_contacts(sinch_client_sync):
diff --git a/tests/e2e/sms/batches/test_batch_sms.py b/tests/e2e/sms/batches/test_batch_sms.py
index b1a20e1d..f28366ff 100644
--- a/tests/e2e/sms/batches/test_batch_sms.py
+++ b/tests/e2e/sms/batches/test_batch_sms.py
@@ -33,7 +33,6 @@ def test_send_sms_zen_of_python(sinch_client_sync, phone_number, origin_phone_nu
             body=line,
             feedback_enabled=True
         )
-
         assert isinstance(send_sms_response, SendSMSBatchResponse)
 
 
@@ -43,7 +42,7 @@ async def test_send_sms_async(sinch_client_async, phone_number, origin_phone_num
         to=[phone_number],
         from_=origin_phone_number,
         body="Asynchronous Spanish Inquisition",
-        feedback_enabled=True,
+        feedback_enabled=True
     )
     assert isinstance(send_sms_response, SendSMSBatchResponse)
 
@@ -54,6 +53,21 @@ def test_send_sms_sync(sinch_client_sync, phone_number, origin_phone_number):
         to=[phone_number],
         from_=origin_phone_number,
         body="Synchronous Spanish Inquisition",
-        feedback_enabled=True,
+        feedback_enabled=True
+    )
+    assert isinstance(send_sms_response, SendSMSBatchResponse)
+
+
+def test_send_sms_sync_with_service_plan_id(
+    sinch_client_sync_with_service_plan_id,
+    phone_number,
+    origin_phone_number
+):
+    send_sms_response = sinch_client_sync_with_service_plan_id.sms.batches.send(
+        delivery_report="none",
+        to=[phone_number],
+        from_=origin_phone_number,
+        body="Synchronous Spanish Inquisition",
+        feedback_enabled=True
     )
     assert isinstance(send_sms_response, SendSMSBatchResponse)
diff --git a/tests/e2e/sms/batches/test_cancel_batch.py b/tests/e2e/sms/batches/test_cancel_batch.py
index 67eb350f..a4bfad51 100644
--- a/tests/e2e/sms/batches/test_cancel_batch.py
+++ b/tests/e2e/sms/batches/test_cancel_batch.py
@@ -16,6 +16,25 @@ def test_cancel_sms_batch(sinch_client_sync, phone_number, origin_phone_number):
     assert isinstance(cancel_batch_response, CancelSMSBatchResponse)
 
 
+def test_cancel_sms_batch_with_service_plan_id(
+        sinch_client_sync_with_service_plan_id,
+    phone_number,
+    origin_phone_number
+):
+    send_batch_response = sinch_client_sync_with_service_plan_id.sms.batches.send(
+        delivery_report="none",
+        to=[phone_number],
+        from_=origin_phone_number,
+        body="Synchronous Batch Cancel",
+        feedback_enabled=True,
+        send_at="2024-08-24T21:37:00Z"
+    )
+    cancel_batch_response = sinch_client_sync_with_service_plan_id.sms.batches.cancel(
+        batch_id=send_batch_response.id
+    )
+    assert isinstance(cancel_batch_response, CancelSMSBatchResponse)
+
+
 async def test_cancel_sms_batch_async(sinch_client_async, phone_number, origin_phone_number):
     send_batch_response = await sinch_client_async.sms.batches.send(
         delivery_report="none",
diff --git a/tests/e2e/sms/batches/test_dry_run.py b/tests/e2e/sms/batches/test_dry_run.py
index 2643f6e7..3070fd4d 100644
--- a/tests/e2e/sms/batches/test_dry_run.py
+++ b/tests/e2e/sms/batches/test_dry_run.py
@@ -12,6 +12,21 @@ def test_send_sms_dry_run(sinch_client_sync, phone_number, origin_phone_number):
     assert isinstance(send_dry_run_response, SendSMSBatchDryRunResponse)
 
 
+def test_send_sms_dry_run_with_service_plan_id(
+        sinch_client_sync_with_service_plan_id,
+    phone_number,
+    origin_phone_number
+):
+    send_dry_run_response = sinch_client_sync_with_service_plan_id.sms.batches.send_dry_run(
+        number_of_recipients=10,
+        per_recipient=True,
+        to=[phone_number],
+        from_=origin_phone_number,
+        body="Spanish Inquisition"
+    )
+    assert isinstance(send_dry_run_response, SendSMSBatchDryRunResponse)
+
+
 async def test_send_sms_dry_run_async(sinch_client_async, phone_number, origin_phone_number):
     send_dry_run_response = await sinch_client_async.sms.batches.send_dry_run(
         number_of_recipients=10,
diff --git a/tests/e2e/sms/batches/test_get_batch.py b/tests/e2e/sms/batches/test_get_batch.py
index e255b254..9a628538 100644
--- a/tests/e2e/sms/batches/test_get_batch.py
+++ b/tests/e2e/sms/batches/test_get_batch.py
@@ -9,6 +9,14 @@ def test_get_sms_batch(sinch_client_sync):
     assert isinstance(get_batch_response, GetSMSBatchResponse)
 
 
+def test_get_sms_batch_with_service_plan_id(sinch_client_sync_with_service_plan_id):
+    list_batch_response = sinch_client_sync_with_service_plan_id.sms.batches.list()
+    get_batch_response = sinch_client_sync_with_service_plan_id.sms.batches.get(
+        batch_id=list_batch_response.result.batches[0].id
+    )
+    assert isinstance(get_batch_response, GetSMSBatchResponse)
+
+
 async def test_get_sms_batch_async(sinch_client_async):
     list_batch_response = await sinch_client_async.sms.batches.list()
     get_batch_response = await sinch_client_async.sms.batches.get(
diff --git a/tests/e2e/sms/batches/test_list_batches.py b/tests/e2e/sms/batches/test_list_batches.py
index 7353f948..42c86bd4 100644
--- a/tests/e2e/sms/batches/test_list_batches.py
+++ b/tests/e2e/sms/batches/test_list_batches.py
@@ -7,9 +7,15 @@ def test_list_sms_batches(sinch_client_sync):
     assert isinstance(list_batches_response, IntBasedPaginator)
 
 
+def test_list_sms_batches_using_service_plan_id(sinch_client_sync_with_service_plan_id):
+    list_batches_response = sinch_client_sync_with_service_plan_id.sms.batches.list()
+    assert isinstance(list_batches_response, IntBasedPaginator)
+    assert len(list_batches_response.result.batches) > 0
+
+
 def test_list_sms_batches_with_page_size_1(sinch_client_sync):
     list_batches_response = sinch_client_sync.sms.batches.list(
-        page_size=1,
+        page_size=1
     )
     assert isinstance(list_batches_response.result, ListSMSBatchesResponse)
     assert len(list_batches_response.result.batches) == 1
diff --git a/tests/e2e/sms/batches/test_replace_batch.py b/tests/e2e/sms/batches/test_replace_batch.py
index f53bfb83..0e0c56d1 100644
--- a/tests/e2e/sms/batches/test_replace_batch.py
+++ b/tests/e2e/sms/batches/test_replace_batch.py
@@ -13,6 +13,21 @@ def test_replace_sms_batch(sinch_client_sync, phone_number):
     assert isinstance(replace_batch_response, ReplaceSMSBatchResponse)
 
 
+def test_replace_sms_batch_with_service_plan_id(
+        sinch_client_sync_with_service_plan_id,
+    phone_number
+):
+    list_batches_response = sinch_client_sync_with_service_plan_id.sms.batches.list(
+        start_date="2022-11-24T14:15:22Z"
+    )
+    replace_batch_response = sinch_client_sync_with_service_plan_id.sms.batches.replace(
+        batch_id=list_batches_response.result.batches[0].id,
+        to=[phone_number],
+        body="Replace SMS batch test"
+    )
+    assert isinstance(replace_batch_response, ReplaceSMSBatchResponse)
+
+
 async def test_replace_sms_batch_async(sinch_client_async, sinch_client_sync, phone_number):
     list_batches_response = sinch_client_sync.sms.batches.list(
         start_date="2022-11-24T14:15:22Z"
diff --git a/tests/e2e/sms/batches/test_send_delivery_feedback.py b/tests/e2e/sms/batches/test_send_delivery_feedback.py
index a3449a7f..a1d096bc 100644
--- a/tests/e2e/sms/batches/test_send_delivery_feedback.py
+++ b/tests/e2e/sms/batches/test_send_delivery_feedback.py
@@ -13,6 +13,15 @@ def test_send_delivery_feedback(sinch_client_sync, phone_number):
     assert isinstance(delivery_feedback_response, SendSMSDeliveryFeedbackResponse)
 
 
+def test_send_delivery_feedback_with_service_plan_id(sinch_client_sync_with_service_plan_id, phone_number):
+    list_batches_response = sinch_client_sync_with_service_plan_id.sms.batches.list()
+    delivery_feedback_response = sinch_client_sync_with_service_plan_id.sms.batches.send_delivery_feedback(
+        batch_id=list_batches_response.result.batches[0].id,
+        recipients=[phone_number]
+    )
+    assert isinstance(delivery_feedback_response, SendSMSDeliveryFeedbackResponse)
+
+
 async def test_send_delivery_feedback_async(sinch_client_async, phone_number):
     list_batches_response = await sinch_client_async.sms.batches.list(
         start_date="2019-08-24T14:15:22Z",
diff --git a/tests/e2e/sms/batches/test_update_batch.py b/tests/e2e/sms/batches/test_update_batch.py
index 96a46950..b0b68b36 100644
--- a/tests/e2e/sms/batches/test_update_batch.py
+++ b/tests/e2e/sms/batches/test_update_batch.py
@@ -1,6 +1,27 @@
 from sinch.domains.sms.models.batches.responses import UpdateSMSBatchResponse
 
 
+def test_update_sms_batch_with_service_plan_id(
+    sinch_client_sync_with_service_plan_id,
+    phone_number,
+    origin_phone_number
+):
+    send_batch_response = sinch_client_sync_with_service_plan_id.sms.batches.send(
+        delivery_report="none",
+        to=[phone_number],
+        from_=origin_phone_number,
+        body="Update Batch Test",
+        feedback_enabled=True,
+        send_at="2024-12-01T21:37:00Z"
+    )
+    update_batch_response = sinch_client_sync_with_service_plan_id.sms.batches.update(
+        batch_id=send_batch_response.id,
+        body="Update Batch Test After Update"
+    )
+    assert isinstance(update_batch_response, UpdateSMSBatchResponse)
+    assert update_batch_response.body == "Update Batch Test After Update"
+
+
 def test_update_sms_batch(sinch_client_sync, phone_number, origin_phone_number):
     send_batch_response = sinch_client_sync.sms.batches.send(
         delivery_report="none",
diff --git a/tests/e2e/sms/delivery_reports/test_get_delivery_report_for_batch.py b/tests/e2e/sms/delivery_reports/test_get_delivery_report_for_batch.py
index 72d2055a..711a7107 100644
--- a/tests/e2e/sms/delivery_reports/test_get_delivery_report_for_batch.py
+++ b/tests/e2e/sms/delivery_reports/test_get_delivery_report_for_batch.py
@@ -19,6 +19,28 @@ def test_get_delivery_reports_for_specific_batch(sinch_client_sync, phone_number
     assert isinstance(get_delivery_report_response, GetSMSDeliveryReportForBatchResponse)
 
 
+def test_get_delivery_reports_for_specific_batch_with_service_plan_id(
+        sinch_client_sync_with_service_plan_id,
+    phone_number,
+    origin_phone_number
+):
+    send_batch_response = sinch_client_sync_with_service_plan_id.sms.batches.send(
+        delivery_report="summary",
+        to=[phone_number],
+        from_=origin_phone_number,
+        body="Delivery report test.",
+        feedback_enabled=True,
+        callback_url="http://testcallback.pl"
+    )
+    get_delivery_report_response = sinch_client_sync_with_service_plan_id.sms.delivery_reports.get_for_batch(
+        batch_id=send_batch_response.id,
+        type_="summary",
+        status=["Queued"],
+        code=[400]
+    )
+    assert isinstance(get_delivery_report_response, GetSMSDeliveryReportForBatchResponse)
+
+
 async def test_get_delivery_reports_for_specific_batch_async(sinch_client_async, phone_number, origin_phone_number):
     send_batch_response = await sinch_client_async.sms.batches.send(
         delivery_report="summary",
diff --git a/tests/e2e/sms/delivery_reports/test_get_delivery_report_for_number.py b/tests/e2e/sms/delivery_reports/test_get_delivery_report_for_number.py
index 64f7e41f..4b2e24b1 100644
--- a/tests/e2e/sms/delivery_reports/test_get_delivery_report_for_number.py
+++ b/tests/e2e/sms/delivery_reports/test_get_delivery_report_for_number.py
@@ -17,6 +17,19 @@ def test_get_delivery_reports_for_specific_number(sinch_client_sync):
     assert isinstance(get_delivery_report_response, GetSMSDeliveryReportForNumberResponse)
 
 
+def test_get_delivery_reports_for_specific_number_with_service_plan_id(sinch_client_sync_with_service_plan_id):
+    list_delivery_reports_response = sinch_client_sync_with_service_plan_id.sms.delivery_reports.list(
+        start_date="2019-08-24T14:15:22Z"
+    )
+    assert isinstance(list_delivery_reports_response.result, ListSMSDeliveryReportsResponse)
+
+    get_delivery_report_response = sinch_client_sync_with_service_plan_id.sms.delivery_reports.get_for_number(
+        batch_id=list_delivery_reports_response.result.delivery_reports[0].batch_id,
+        recipient_number=list_delivery_reports_response.result.delivery_reports[0].recipient
+    )
+    assert isinstance(get_delivery_report_response, GetSMSDeliveryReportForNumberResponse)
+
+
 async def test_get_delivery_reports_for_specific_number_async(sinch_client_async, sinch_client_sync):
     list_delivery_reports_response = sinch_client_sync.sms.delivery_reports.list(
         start_date="2019-08-24T14:15:22Z"
diff --git a/tests/e2e/sms/delivery_reports/test_get_delivery_reports_for_project.py b/tests/e2e/sms/delivery_reports/test_get_delivery_reports_for_project.py
index d7b5e0d1..c9bdcc05 100644
--- a/tests/e2e/sms/delivery_reports/test_get_delivery_reports_for_project.py
+++ b/tests/e2e/sms/delivery_reports/test_get_delivery_reports_for_project.py
@@ -8,6 +8,13 @@ def test_get_delivery_reports_for_project(sinch_client_sync):
     assert isinstance(list_delivery_reports_response.result, ListSMSDeliveryReportsResponse)
 
 
+def test_get_delivery_reports_for_project_with_service_plan_id(sinch_client_sync_with_service_plan_id):
+    list_delivery_reports_response = sinch_client_sync_with_service_plan_id.sms.delivery_reports.list(
+        start_date="2019-08-24T14:15:22Z"
+    )
+    assert isinstance(list_delivery_reports_response.result, ListSMSDeliveryReportsResponse)
+
+
 async def test_get_delivery_reports_for_project_async(sinch_client_async):
     list_delivery_reports_response = await sinch_client_async.sms.delivery_reports.list()
     assert isinstance(list_delivery_reports_response.result, ListSMSDeliveryReportsResponse)
diff --git a/tests/e2e/sms/groups/test_create_group.py b/tests/e2e/sms/groups/test_create_group.py
index af46cc57..a2ef1fd3 100644
--- a/tests/e2e/sms/groups/test_create_group.py
+++ b/tests/e2e/sms/groups/test_create_group.py
@@ -9,6 +9,14 @@ def test_create_sms_group(sinch_client_sync, phone_number):
     assert isinstance(create_group_response, CreateSMSGroupResponse)
 
 
+def test_create_sms_group_with_service_plan_id(sinch_client_sync_with_service_plan_id, phone_number):
+    create_group_response = sinch_client_sync_with_service_plan_id.sms.groups.create(
+        name="KillerRabbit",
+        members=[phone_number]
+    )
+    assert isinstance(create_group_response, CreateSMSGroupResponse)
+
+
 async def test_create_sms_group_async_using_child_groups(sinch_client_async, phone_number):
     create_group_response = await sinch_client_async.sms.groups.create(
         name="KillerRabbit2",
diff --git a/tests/e2e/sms/groups/test_delete_group.py b/tests/e2e/sms/groups/test_delete_group.py
index 50b575d6..ba1a6390 100644
--- a/tests/e2e/sms/groups/test_delete_group.py
+++ b/tests/e2e/sms/groups/test_delete_group.py
@@ -10,6 +10,15 @@ def test_delete_sms_group(sinch_client_sync):
     assert isinstance(delete_group_response, SinchDeleteSMSGroupResponse)
 
 
+def test_delete_sms_group_with_service_plan_id(sinch_client_sync_with_service_plan_id):
+    list_group_response = sinch_client_sync_with_service_plan_id.sms.groups.list()
+
+    delete_group_response = sinch_client_sync_with_service_plan_id.sms.groups.delete(
+        group_id=list_group_response.result.groups[0].id
+    )
+    assert isinstance(delete_group_response, SinchDeleteSMSGroupResponse)
+
+
 async def test_delete_sms_group_async(sinch_client_async):
     list_group_response = await sinch_client_async.sms.groups.list()
 
diff --git a/tests/e2e/sms/groups/test_get_group.py b/tests/e2e/sms/groups/test_get_group.py
index 5fb4b73d..a995201f 100644
--- a/tests/e2e/sms/groups/test_get_group.py
+++ b/tests/e2e/sms/groups/test_get_group.py
@@ -1,6 +1,15 @@
 from sinch.domains.sms.models.groups.responses import GetSMSGroupResponse
 
 
+def test_get_sms_group_with_service_plan_id(sinch_client_sync_with_service_plan_id):
+    list_group_response = sinch_client_sync_with_service_plan_id.sms.groups.list()
+
+    get_group_response = sinch_client_sync_with_service_plan_id.sms.groups.get(
+        group_id=list_group_response.result.groups[0].id
+    )
+    assert isinstance(get_group_response, GetSMSGroupResponse)
+
+
 def test_get_sms_group(sinch_client_sync):
     list_group_response = sinch_client_sync.sms.groups.list()
 
diff --git a/tests/e2e/sms/groups/test_get_phone_numbers_for_group.py b/tests/e2e/sms/groups/test_get_phone_numbers_for_group.py
index eb72bd58..584547f3 100644
--- a/tests/e2e/sms/groups/test_get_phone_numbers_for_group.py
+++ b/tests/e2e/sms/groups/test_get_phone_numbers_for_group.py
@@ -1,6 +1,17 @@
 from sinch.domains.sms.models.groups.responses import SinchGetSMSGroupPhoneNumbersResponse
 
 
+def test_get_group_phone_numbers_sms_with_service_plan_id(sinch_client_sync_with_service_plan_id):
+    list_group_response = sinch_client_sync_with_service_plan_id.sms.groups.list()
+
+    get_group_response = sinch_client_sync_with_service_plan_id.sms.groups.get_group_phone_numbers(
+        group_id=list_group_response.result.groups[0].id
+    )
+
+    assert isinstance(get_group_response, SinchGetSMSGroupPhoneNumbersResponse)
+    assert get_group_response.phone_numbers
+
+
 def test_get_group_phone_numbers_sms(sinch_client_sync):
     list_group_response = sinch_client_sync.sms.groups.list()
 
diff --git a/tests/e2e/sms/groups/test_list_groups.py b/tests/e2e/sms/groups/test_list_groups.py
index 1c1db513..3190e398 100644
--- a/tests/e2e/sms/groups/test_list_groups.py
+++ b/tests/e2e/sms/groups/test_list_groups.py
@@ -7,6 +7,11 @@ def test_list_sms_groups(sinch_client_sync):
     assert isinstance(list_group_response.result, SinchListSMSGroupResponse)
 
 
+def test_list_sms_groups_with_service_plan_id(sinch_client_sync_with_service_plan_id):
+    list_group_response = sinch_client_sync_with_service_plan_id.sms.groups.list()
+    assert isinstance(list_group_response.result, SinchListSMSGroupResponse)
+
+
 async def test_list_sms_groups_async(sinch_client_async):
     list_group_response = await sinch_client_async.sms.groups.list()
     assert isinstance(list_group_response.result, SinchListSMSGroupResponse)
diff --git a/tests/e2e/sms/groups/test_replace_group.py b/tests/e2e/sms/groups/test_replace_group.py
index 7861862c..74e1c2ad 100644
--- a/tests/e2e/sms/groups/test_replace_group.py
+++ b/tests/e2e/sms/groups/test_replace_group.py
@@ -1,6 +1,16 @@
 from sinch.domains.sms.models.groups.responses import ReplaceSMSGroupResponse
 
 
+def test_replace_sms_group_with_service_plan_id(sinch_client_sync_with_service_plan_id):
+    list_group_response = sinch_client_sync_with_service_plan_id.sms.groups.list()
+
+    replace_group_response = sinch_client_sync_with_service_plan_id.sms.groups.replace(
+        group_id=list_group_response.result.groups[0].id,
+        members=["48111111111"]
+    )
+    assert isinstance(replace_group_response, ReplaceSMSGroupResponse)
+
+
 def test_replace_sms_group(sinch_client_sync):
     list_group_response = sinch_client_sync.sms.groups.list()
 
diff --git a/tests/e2e/sms/groups/test_update_group.py b/tests/e2e/sms/groups/test_update_group.py
index c56a92ee..ffcab07d 100644
--- a/tests/e2e/sms/groups/test_update_group.py
+++ b/tests/e2e/sms/groups/test_update_group.py
@@ -1,4 +1,5 @@
 from sinch.domains.sms.models.groups.responses import UpdateSMSGroupResponse
+from sinch.core.enums import HTTPAuthentication
 
 
 def test_update_sms_group(sinch_client_sync, phone_number):
@@ -12,6 +13,17 @@ def test_update_sms_group(sinch_client_sync, phone_number):
     assert update_group_response.name == "KillerRabbit222"
 
 
+def test_update_sms_group_with_service_plan_id(sinch_client_sync_with_service_plan_id, phone_number):
+    list_group_response = sinch_client_sync_with_service_plan_id.sms.groups.list()
+
+    update_group_response = sinch_client_sync_with_service_plan_id.sms.groups.update(
+        name="KillerRabbit222",
+        group_id=list_group_response.result.groups[0].id
+    )
+    assert isinstance(update_group_response, UpdateSMSGroupResponse)
+    assert update_group_response.name == "KillerRabbit222"
+
+
 def test_add_phone_number_to_sms_group(sinch_client_sync, phone_number):
     list_group_response = sinch_client_sync.sms.groups.list()
 
diff --git a/tests/e2e/sms/inbounds/test_list_inbound_messages.py b/tests/e2e/sms/inbounds/test_list_inbound_messages.py
index 58cece3b..85e00405 100644
--- a/tests/e2e/sms/inbounds/test_list_inbound_messages.py
+++ b/tests/e2e/sms/inbounds/test_list_inbound_messages.py
@@ -6,6 +6,11 @@ def test_list_inbound_sms(sinch_client_sync):
     assert isinstance(list_incoming_message_response.result, SinchListInboundMessagesResponse)
 
 
+def test_list_inbound_sms_with_service_plan_id(sinch_client_sync_with_service_plan_id):
+    list_incoming_message_response = sinch_client_sync_with_service_plan_id.sms.inbounds.list()
+    assert isinstance(list_incoming_message_response.result, SinchListInboundMessagesResponse)
+
+
 async def test_list_inbound_sms_async(sinch_client_async):
     list_incoming_message_response = await sinch_client_async.sms.inbounds.list()
     assert isinstance(list_incoming_message_response.result, SinchListInboundMessagesResponse)
diff --git a/tests/integration/test_domain_endpoint_error_handling.py b/tests/integration/test_domain_endpoint_error_handling.py
index 428875ac..59cb6f3d 100644
--- a/tests/integration/test_domain_endpoint_error_handling.py
+++ b/tests/integration/test_domain_endpoint_error_handling.py
@@ -34,10 +34,10 @@ def test_conversation_endpoint_error_handling(project_id, http_response):
         assert error.response_status_code == http_response.status_code
 
 
-def test_sms_endpoint_error_handling(project_id, sms_http_response):
+def test_sms_endpoint_error_handling(sinch_client_sync, sms_http_response):
     numbers_endpoint = SMSEndpoint(
-        project_id=project_id,
-        request_data={}
+        request_data={},
+        sinch=sinch_client_sync
     )
     with pytest.raises(SMSException) as error:
         numbers_endpoint.handle_response(sms_http_response)
diff --git a/tests/integration/test_http_transport.py b/tests/integration/test_http_transport.py
new file mode 100644
index 00000000..af4e44a8
--- /dev/null
+++ b/tests/integration/test_http_transport.py
@@ -0,0 +1,41 @@
+from sinch.core.adapters.requests_http_transport import HTTPTransportRequests
+from sinch.domains.sms.endpoints.batches.send_batch import SendBatchSMSEndpoint
+
+
+def test_authenticate_method_with_service_plan_id_version_of_sms_api(
+    sinch_client_sync_with_service_plan_id,
+    empty_http_request
+):
+    sms_endpoint = SendBatchSMSEndpoint(
+        sinch=sinch_client_sync_with_service_plan_id,
+        request_data=empty_http_request
+    )
+    http_transport = HTTPTransportRequests(sinch=sinch_client_sync_with_service_plan_id)
+    http_transport.authenticate(endpoint=sms_endpoint, request_data=empty_http_request)
+
+    assert empty_http_request.headers
+    assert "Bearer" in empty_http_request.headers["Authorization"]
+    assert (
+        empty_http_request.headers["Authorization"] ==
+        f"Bearer {sinch_client_sync_with_service_plan_id.configuration.sms_api_token}"
+    )
+    assert empty_http_request.headers["Content-Type"] == "application/json"
+
+
+def test_authenticate_method_with_project_id_version_of_sms_api(
+    sinch_client_sync,
+    empty_http_request
+):
+    sms_endpoint = SendBatchSMSEndpoint(
+        sinch=sinch_client_sync,
+        request_data=empty_http_request,
+    )
+    http_transport = HTTPTransportRequests(sinch=sinch_client_sync)
+    http_transport.authenticate(endpoint=sms_endpoint, request_data=empty_http_request)
+
+    assert empty_http_request.headers
+    assert (
+        empty_http_request.headers["Authorization"] ==
+        f"Bearer {sinch_client_sync.configuration.token_manager.token.access_token}"
+    )
+    assert empty_http_request.headers["Content-Type"] == "application/json"
diff --git a/tests/integration/test_sms_endpoint_credendials_formatting.py b/tests/integration/test_sms_endpoint_credendials_formatting.py
new file mode 100644
index 00000000..4c8a0151
--- /dev/null
+++ b/tests/integration/test_sms_endpoint_credendials_formatting.py
@@ -0,0 +1,23 @@
+from sinch.domains.sms.endpoints.sms_endpoint import SMSEndpoint
+from sinch.core.enums import HTTPAuthentication
+
+
+def test_sms_endpoint_service_plan_id_credentials_processing(sinch_client_sync_with_service_plan_id, service_plan_id):
+    sms_endpoint = SMSEndpoint(
+        sinch=sinch_client_sync_with_service_plan_id,
+        request_data={}
+    )
+    assert sms_endpoint.project_or_service_id == service_plan_id
+    assert sms_endpoint.HTTP_AUTHENTICATION == HTTPAuthentication.SMS_TOKEN.value
+    assert (
+        sms_endpoint.sms_origin == sinch_client_sync_with_service_plan_id.configuration.sms_origin_with_service_plan_id
+    )
+
+
+def test_sms_endpoint_with_project_id_credentials_processing(sinch_client_sync, project_id):
+    sms_endpoint = SMSEndpoint(
+        sinch=sinch_client_sync,
+        request_data={}
+    )
+    assert sms_endpoint.project_or_service_id == project_id
+    assert sms_endpoint.sms_origin == sinch_client_sync.configuration.sms_origin
diff --git a/tests/unit/test_configuration.py b/tests/unit/test_configuration.py
index fb83355d..da5815b7 100644
--- a/tests/unit/test_configuration.py
+++ b/tests/unit/test_configuration.py
@@ -19,29 +19,28 @@ def test_configuration_initialization_happy_path(sinch_client_sync):
 
 
 def test_set_sms_region_property_and_check_that_sms_origin_was_updated(sinch_client_sync):
-    sinch_client_sync.configuration.sms_region = (
-        "We interrupt this program to annoy you" 
-        "and make things generally more irritating."
-    )
-    assert "irritating" in sinch_client_sync.configuration.sms_origin
+    sinch_client_sync.configuration.sms_region = "pl"
+    assert "zt.pl.sms.api.sinch.com" == sinch_client_sync.configuration.sms_origin
 
 
 def test_set_sms_domain_property_and_check_that_sms_origin_was_updated(sinch_client_sync):
-    sinch_client_sync.configuration.sms_region = (
-        "We interrupt this program to annoy you" 
-        "and make things generally more irritating."
-    )
-    assert "irritating" in sinch_client_sync.configuration.sms_origin
+    sinch_client_sync.configuration.sms_domain = "{}.monty.python"
+    assert "us.monty.python" == sinch_client_sync.configuration.sms_origin
+
+
+def test_set_sms_region_with_service_plan_id_property_and_check_that_sms_origin_was_updated(sinch_client_sync):
+    sinch_client_sync.configuration.sms_region_with_service_plan_id = "Herring"
+    assert sinch_client_sync.configuration.sms_origin_with_service_plan_id.startswith("Herring")
 
 
 def test_set_conversation_region_property_and_check_that_sms_origin_was_updated(sinch_client_sync):
-    sinch_client_sync.configuration.conversation_region = "My_brain_hurts!"
+    sinch_client_sync.configuration.conversation_region = "My_brain_hurts"
     assert "brain" in sinch_client_sync.configuration.conversation_origin
     assert "hurts" in sinch_client_sync.configuration.conversation_origin
 
 
 def test_set_conversation_domain_property_and_check_that_sms_origin_was_updated(sinch_client_sync):
-    sinch_client_sync.configuration.conversation_domain= "My_brain_hurts!"
+    sinch_client_sync.configuration.conversation_domain= "My_brain_hurts"
     assert "brain" in sinch_client_sync.configuration.conversation_origin
     assert "hurts" in sinch_client_sync.configuration.conversation_origin