diff --git a/litellm/llms/base_llm/realtime/transformation.py b/litellm/llms/base_llm/realtime/transformation.py
index d5531a532b9..22768110be9 100644
--- a/litellm/llms/base_llm/realtime/transformation.py
+++ b/litellm/llms/base_llm/realtime/transformation.py
@@ -69,6 +69,20 @@ class BaseRealtimeConfig(ABC):
     ) -> Optional[str]:  # message sent to setup the realtime session
         return None
 
+    def transform_session_created_event(
+        self,
+        model: str,
+        logging_session_id: str,
+        session_configuration_request: Optional[str] = None,
+    ) -> Optional[dict]:
+        """
+        Optional hook for providers that defer session setup until client `session.update`.
+
+        Return an OpenAI-compatible `session.created` payload when the proxy should
+        emit a synthetic event immediately after backend websocket connection.
+        """
+        return None
+
     @abstractmethod
     def transform_realtime_response(
         self,
diff --git a/litellm/llms/custom_httpx/llm_http_handler.py b/litellm/llms/custom_httpx/llm_http_handler.py
index 1a73002f1b4..270aaaa84da 100644
--- a/litellm/llms/custom_httpx/llm_http_handler.py
+++ b/litellm/llms/custom_httpx/llm_http_handler.py
@@ -5156,20 +5156,19 @@ class BaseLLMHTTPHandler:
                 if _session_config:
                     realtime_streaming.session_configuration_request = _session_config
                 
-                # For Gemini/Vertex AI: if no initial setup sent (waiting for client's session.update),
-                # send synthetic session.created to unblock client
-                if not provider_config.requires_session_configuration() and hasattr(
-                    provider_config, 'transform_session_created_event'
-                ):
+                # For providers that defer setup until client session.update, optionally
+                # send synthetic session.created to unblock clients waiting on connect.
+                if not provider_config.requires_session_configuration():
                     synthetic_session = provider_config.transform_session_created_event(
                         model=model,
                         logging_session_id=logging_obj.litellm_trace_id,
                         session_configuration_request=None,
                     )
-                    await websocket.send_text(json.dumps(synthetic_session))
-                    verbose_logger.debug(
-                        "Sent synthetic session.created to client to unblock connection"
-                    )
+                    if synthetic_session is not None:
+                        await websocket.send_text(json.dumps(synthetic_session))
+                        verbose_logger.debug(
+                            "Sent synthetic session.created to client to unblock connection"
+                        )
                 
                 await realtime_streaming.bidirectional_forward()