diff --git a/litellm/llms/openai.py b/litellm/llms/openai.py
index e7baaf834e..efc8808212 100644
--- a/litellm/llms/openai.py
+++ b/litellm/llms/openai.py
@@ -154,18 +154,36 @@ class OpenAITextCompletionConfig():
                 and v is not None}
 
 class OpenAIChatCompletion(BaseLLM):
-    _client_session: Optional[httpx.Client] = None
-    _aclient_session: Optional[httpx.AsyncClient] = None
+    openai_client: Optional[openai.Client] = None
+    openai_aclient: Optional[openai.AsyncClient] = None
 
     def __init__(self) -> None:
         super().__init__()
+        self.openai_client = openai.OpenAI()
+        self.openai_aclient = openai.AsyncOpenAI()
     
-    def validate_environment(self, api_key):
-        headers = {
-            "content-type": "application/json",
-        }
-        if api_key:
-            headers["Authorization"] = f"Bearer {api_key}"
+    def validate_environment(self, api_key, api_base, headers):
+        if headers is None: 
+            headers = {
+                "content-type": "application/json",
+            }
+            if api_key: 
+                headers["Authorization"] = f"Bearer {api_key}"
+        
+        self.openai_client.api_key = api_key
+        self.openai_aclient.api_key = api_key
+        if api_base: 
+            if self.openai_client.base_url is None or self.openai_client.base_url != api_base:
+                if api_base.endswith("/"):
+                    self.openai_client._base_url = httpx.URL(url=api_base)
+                else: 
+                    self.openai_client._base_url = httpx.URL(url=api_base+"/")
+            if self.openai_aclient.base_url is None or self.openai_aclient.base_url != api_base:
+                if api_base.endswith("/"):
+                    self.openai_aclient._base_url = httpx.URL(url=api_base)
+                else: 
+                    self.openai_aclient._base_url = httpx.URL(url=api_base+"/")
+        
         return headers
     
     def _retry_request(self, *args, **kwargs): 
@@ -191,13 +209,9 @@ class OpenAIChatCompletion(BaseLLM):
                 logger_fn=None,
                 headers: Optional[dict]=None):
         super().completion()
-        if self._client_session is None:
-            self._client_session = self.create_client_session()
         exception_mapping_worked = False
         try: 
-            if headers is None:
-                headers = self.validate_environment(api_key=api_key)
-            api_base = f"{api_base}/chat/completions"
+            headers = self.validate_environment(api_key=api_key, api_base=api_base, headers=headers)
             if model is None or messages is None:
                 raise OpenAIError(status_code=422, message=f"Missing model or messages")
             
@@ -224,23 +238,8 @@ class OpenAIChatCompletion(BaseLLM):
                     elif optional_params.get("stream", False):
                         return self.streaming(logging_obj=logging_obj, api_base=api_base, data=data, headers=headers, model_response=model_response, model=model)
                     else:
-                        if model in litellm.models_by_provider["openai"]:
-                            if api_key:
-                                openai.api_key = api_key
-                            response = openai.chat.completions.create(**data)
-                            return convert_to_model_response_object(response_object=json.loads(response.model_dump_json()), model_response_object=model_response)
-                        else: 
-                            response = requests.post(
-                                url=api_base,
-                                json=data,
-                                headers=headers,
-                                timeout=600 # Set a 10-minute timeout for both connection and read
-                            )
-                            if response.status_code != 200:
-                                raise OpenAIError(status_code=response.status_code, message=response.text)
-                            
-                            ## RESPONSE OBJECT
-                            return convert_to_model_response_object(response_object=response.json(), model_response_object=model_response)
+                        response = self.openai_client.chat.completions.create(**data)
+                        return convert_to_model_response_object(response_object=json.loads(response.model_dump_json()), model_response_object=model_response)
                 except Exception as e:
                     if "Conversation roles must alternate user/assistant" in str(e) or "user and assistant roles should be alternating" in str(e): 
                         # reformat messages to ensure user/assistant are alternating, if there's either 2 consecutive 'user' messages or 2 consecutive 'assistant' message, add a blank 'user' or 'assistant' message to ensure compatibility
@@ -270,19 +269,11 @@ class OpenAIChatCompletion(BaseLLM):
                           api_base: str, 
                           data: dict, headers: dict, 
                           model_response: ModelResponse): 
-        kwargs = locals()
+        response = None
         try: 
-            async with httpx.AsyncClient() as client:
-                response = await client.post(api_base, json=data, headers=headers, timeout=litellm.request_timeout) 
-                response_json = response.json()
-                if response.status_code != 200:
-                    raise OpenAIError(status_code=response.status_code, message=response.text, request=response.request, response=response)
-                
-                ## RESPONSE OBJECT
-                return convert_to_model_response_object(response_object=response_json, model_response_object=model_response)
+            response = await self.openai_aclient.chat.completions.create(**data)
+            return convert_to_model_response_object(response_object=json.loads(response.model_dump_json()), model_response_object=model_response)
         except Exception as e: 
-            if isinstance(e, httpx.TimeoutException):
-                raise OpenAIError(status_code=500, message="Request Timeout Error")
             if response and hasattr(response, "text"):
                 raise OpenAIError(status_code=500, message=f"{str(e)}\n\nOriginal Response: {response.text}")
             else: 
@@ -296,20 +287,10 @@ class OpenAIChatCompletion(BaseLLM):
                   model_response: ModelResponse, 
                   model: str
     ):
-        with httpx.stream(
-                    url=f"{api_base}", # type: ignore
-                    json=data,
-                    headers=headers,
-                    method="POST",
-                    timeout=litellm.request_timeout 
-                ) as response: 
-                    if response.status_code != 200:
-                        raise OpenAIError(status_code=response.status_code, message=response.text()) # type: ignore
-                    
-                    completion_stream = response.iter_lines()
-                    streamwrapper = CustomStreamWrapper(completion_stream=completion_stream, model=model, custom_llm_provider="openai",logging_obj=logging_obj)
-                    for transformed_chunk in streamwrapper:
-                        yield transformed_chunk
+        response = self.openai_client.chat.completions.create(**data)
+        streamwrapper = CustomStreamWrapper(completion_stream=response, model=model, custom_llm_provider="openai",logging_obj=logging_obj)
+        for transformed_chunk in streamwrapper:
+            yield transformed_chunk
 
     async def async_streaming(self, 
                           logging_obj,
@@ -318,20 +299,11 @@ class OpenAIChatCompletion(BaseLLM):
                           headers: dict, 
                           model_response: ModelResponse, 
                           model: str):
-        client = httpx.AsyncClient()
-        async with client.stream(
-                    url=f"{api_base}",
-                    json=data,
-                    headers=headers,
-                    method="POST",
-                    timeout=litellm.request_timeout
-                ) as response: 
-            if response.status_code != 200:
-                raise OpenAIError(status_code=response.status_code, message=response.text()) # type: ignore
-            
-            streamwrapper = CustomStreamWrapper(completion_stream=response.aiter_lines(), model=model, custom_llm_provider="openai",logging_obj=logging_obj)
-            async for transformed_chunk in streamwrapper:
-                yield transformed_chunk
+        response = await self.openai_aclient.chat.completions.create(**data)
+        streamwrapper = CustomStreamWrapper(completion_stream=response, model=model, custom_llm_provider="openai",logging_obj=logging_obj)
+        async for transformed_chunk in streamwrapper:
+            yield transformed_chunk
+
 
     def embedding(self,
                 model: str,
diff --git a/litellm/llms/vertex_ai.py b/litellm/llms/vertex_ai.py
index df34a25496..bbb23a0c2f 100644
--- a/litellm/llms/vertex_ai.py
+++ b/litellm/llms/vertex_ai.py
@@ -12,7 +12,7 @@ class VertexAIError(Exception):
     def __init__(self, status_code, message):
         self.status_code = status_code
         self.message = message
-        self.request = httpx.Request(method="POST", url="https://api.ai21.com/studio/v1/")
+        self.request = httpx.Request(method="POST", url=" https://cloud.google.com/vertex-ai/")
         self.response = httpx.Response(status_code=status_code, request=self.request)
         super().__init__(
             self.message
diff --git a/litellm/tests/test_async_fn.py b/litellm/tests/test_async_fn.py
index 920fff3cc5..80981a62e9 100644
--- a/litellm/tests/test_async_fn.py
+++ b/litellm/tests/test_async_fn.py
@@ -23,7 +23,18 @@ def test_sync_response():
         response = completion(model="gpt-3.5-turbo", messages=messages, api_key=os.environ["OPENAI_API_KEY"])
     except Exception as e:
         pytest.fail(f"An exception occurred: {e}")
+# test_sync_response()
 
+def test_sync_response_anyscale():
+    litellm.set_verbose = True
+    user_message = "Hello, how are you?"
+    messages = [{"content": user_message, "role": "user"}]
+    try:
+        response = completion(model="anyscale/mistralai/Mistral-7B-Instruct-v0.1", messages=messages)
+    except Exception as e:
+        pytest.fail(f"An exception occurred: {e}")
+
+# test_sync_response_anyscale()
 
 def test_async_response():
     import asyncio
@@ -32,13 +43,28 @@ def test_async_response():
         user_message = "Hello, how are you?"
         messages = [{"content": user_message, "role": "user"}]
         try:
-            response = await acompletion(model="huggingface/HuggingFaceH4/zephyr-7b-beta", messages=messages)
+            response = await acompletion(model="gpt-3.5-turbo", messages=messages)
+            # response = await response
+            print(f"response: {response}")
+        except Exception as e:
+            pytest.fail(f"An exception occurred: {e}")
+
+    asyncio.run(test_get_response())
+
+def test_async_anyscale_response():
+    import asyncio
+    litellm.set_verbose = True
+    async def test_get_response():
+        user_message = "Hello, how are you?"
+        messages = [{"content": user_message, "role": "user"}]
+        try:
+            response = await acompletion(model="anyscale/mistralai/Mistral-7B-Instruct-v0.1", messages=messages)
+            # response = await response
             print(f"response: {response}")
         except Exception as e:
             pytest.fail(f"An exception occurred: {e}")
 
     asyncio.run(test_get_response())
-# test_async_response()
 
 def test_get_response_streaming():
     import asyncio
@@ -70,7 +96,7 @@ def test_get_response_streaming():
     asyncio.run(test_async_call())
 
 
-# test_get_response_streaming()
+test_get_response_streaming()
 
 def test_get_response_non_openai_streaming():
     import asyncio
@@ -79,7 +105,7 @@ def test_get_response_non_openai_streaming():
         user_message = "Hello, how are you?"
         messages = [{"content": user_message, "role": "user"}]
         try:
-            response = await acompletion(model="huggingface/HuggingFaceH4/zephyr-7b-beta", messages=messages, stream=True)
+            response = await acompletion(model="anyscale/mistralai/Mistral-7B-Instruct-v0.1", messages=messages, stream=True)
             print(type(response))
 
             import inspect
diff --git a/litellm/tests/test_streaming.py b/litellm/tests/test_streaming.py
index 314b8736b6..a7f7772687 100644
--- a/litellm/tests/test_streaming.py
+++ b/litellm/tests/test_streaming.py
@@ -374,7 +374,7 @@ def test_completion_azure_stream():
         print(f"completion_response: {complete_response}")
     except Exception as e:
         pytest.fail(f"Error occurred: {e}")
-test_completion_azure_stream() 
+# test_completion_azure_stream() 
 
 def test_completion_claude_stream():
     try:
@@ -829,6 +829,7 @@ def ai21_completion_call_bad_key():
 def test_openai_chat_completion_call():
     try:
         litellm.set_verbose = False
+        print(f"making openai chat completion call")
         response = completion(
             model="gpt-3.5-turbo", messages=messages, stream=True
         )
@@ -848,7 +849,7 @@ def test_openai_chat_completion_call():
         print(f"error occurred: {traceback.format_exc()}")
         pass
 
-# test_openai_chat_completion_call()
+test_openai_chat_completion_call()
 
 def test_openai_chat_completion_complete_response_call():
     try:
diff --git a/litellm/utils.py b/litellm/utils.py
index 0e0a4ced9a..63c470f0a2 100644
--- a/litellm/utils.py
+++ b/litellm/utils.py
@@ -4496,26 +4496,12 @@ class CustomStreamWrapper:
             text = "" 
             is_finished = False
             finish_reason = None
-            if "data: [DONE]" in str_line:
-                # anyscale returns a [DONE] special char for streaming, this cannot be json loaded. This is the end of stream
-                text = ""
+            if str_line.choices[0].delta.content is not None:
+                text = str_line.choices[0].delta.content
+            if str_line.choices[0].finish_reason:
                 is_finished = True
-                finish_reason = "stop"
-                return {"text": text, "is_finished": is_finished, "finish_reason": finish_reason}
-            elif str_line.startswith("data:") and len(str_line[5:]) > 0:
-                str_line = str_line[5:]
-                data_json = json.loads(str_line)
-                print_verbose(f"delta content: {data_json['choices'][0]['delta']}")
-                text = data_json["choices"][0]["delta"].get("content", "") 
-                if data_json["choices"][0].get("finish_reason", None): 
-                    is_finished = True
-                    finish_reason = data_json["choices"][0]["finish_reason"]
-                return {"text": text, "is_finished": is_finished, "finish_reason": finish_reason}
-            elif "error" in str_line:
-                raise ValueError(f"Unable to parse response. Original response: {str_line}")
-            else:
-                return {"text": text, "is_finished": is_finished, "finish_reason": finish_reason}
-
+                finish_reason = str_line.choices[0].finish_reason
+            return {"text": text, "is_finished": is_finished, "finish_reason": finish_reason}
         except Exception as e:
             traceback.print_exc()
             raise e