diff --git a/.circleci/config.yml b/.circleci/config.yml
index 585502710..efc0c720c 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -363,6 +363,100 @@ jobs:
       - store_test_results:
           path: test-results
 
+  proxy_pass_through_endpoint_tests:
+    machine:
+      image: ubuntu-2204:2023.10.1
+    resource_class: xlarge
+    working_directory: ~/project
+    steps:
+      - checkout
+      - run:
+          name: Install Docker CLI (In case it's not already installed)
+          command: |
+            sudo apt-get update
+            sudo apt-get install -y docker-ce docker-ce-cli containerd.io
+      - run:
+          name: Install Python 3.9
+          command: |
+            curl https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh --output miniconda.sh
+            bash miniconda.sh -b -p $HOME/miniconda
+            export PATH="$HOME/miniconda/bin:$PATH"
+            conda init bash
+            source ~/.bashrc
+            conda create -n myenv python=3.9 -y
+            conda activate myenv
+            python --version
+      - run:
+          name: Install Dependencies
+          command: |
+            pip install "pytest==7.3.1"
+            pip install "pytest-retry==1.6.3"
+            pip install "pytest-asyncio==0.21.1"
+            pip install "google-cloud-aiplatform==1.43.0"
+            pip install aiohttp
+            pip install "openai==1.40.0"
+            python -m pip install --upgrade pip
+            pip install "pydantic==2.7.1"
+            pip install "pytest==7.3.1"
+            pip install "pytest-mock==3.12.0"
+            pip install "pytest-asyncio==0.21.1"
+            pip install "boto3==1.34.34"
+            pip install mypy
+            pip install pyarrow
+            pip install numpydoc
+            pip install prisma            
+            pip install fastapi            
+            pip install jsonschema   
+            pip install "httpx==0.24.1"
+            pip install "anyio==3.7.1"
+            pip install "asyncio==3.4.3"
+            pip install "PyGithub==1.59.1"
+      - run:
+          name: Build Docker image
+          command: docker build -t my-app:latest -f Dockerfile.database .
+      - run:
+          name: Run Docker container
+          command: |
+            docker run -d \
+              -p 4000:4000 \
+              -e DATABASE_URL=$PROXY_DATABASE_URL \
+              -e LITELLM_MASTER_KEY="sk-1234" \
+              -e OPENAI_API_KEY=$OPENAI_API_KEY \
+              -e LITELLM_LICENSE=$LITELLM_LICENSE \
+              --name my-app \
+              -v $(pwd)/litellm/proxy/example_config_yaml/pass_through_config.yaml:/app/config.yaml \
+              -v $(pwd)/litellm/proxy/example_config_yaml/custom_auth_basic.py:/app/custom_auth_basic.py \
+              my-app:latest \
+              --config /app/config.yaml \
+              --port 4000 \
+              --detailed_debug \
+      - run:
+          name: Install curl and dockerize
+          command: |
+            sudo apt-get update
+            sudo apt-get install -y curl
+            sudo wget https://github.com/jwilder/dockerize/releases/download/v0.6.1/dockerize-linux-amd64-v0.6.1.tar.gz
+            sudo tar -C /usr/local/bin -xzvf dockerize-linux-amd64-v0.6.1.tar.gz
+            sudo rm dockerize-linux-amd64-v0.6.1.tar.gz
+      - run:
+          name: Start outputting logs
+          command: docker logs -f my-app
+          background: true
+      - run:
+          name: Wait for app to be ready
+          command: dockerize -wait http://localhost:4000 -timeout 5m
+      - run:
+          name: Run tests
+          command: |
+            pwd
+            ls
+            python -m pytest -vv tests/pass_through_tests/test_vertex_ai.py -x --junitxml=test-results/junit.xml --durations=5
+          no_output_timeout: 120m
+
+      # Store test results
+      - store_test_results:
+          path: test-results
+
   publish_to_pypi:
     docker:
       - image: cimg/python:3.8
@@ -457,6 +551,12 @@ workflows:
               only:
                 - main
                 - /litellm_.*/
+      - proxy_pass_through_endpoint_tests:
+          filters:
+            branches:
+              only:
+                - main
+                - /litellm_.*/
       - installing_litellm_on_python:
           filters:
             branches:
@@ -468,6 +568,7 @@ workflows:
             - local_testing
             - build_and_test
             - proxy_log_to_otel_tests
+            - proxy_pass_through_endpoint_tests
           filters:
             branches:
               only:
diff --git a/litellm/proxy/example_config_yaml/custom_auth_basic.py b/litellm/proxy/example_config_yaml/custom_auth_basic.py
new file mode 100644
index 000000000..2726b1c3d
--- /dev/null
+++ b/litellm/proxy/example_config_yaml/custom_auth_basic.py
@@ -0,0 +1,14 @@
+from fastapi import Request
+
+from litellm.proxy._types import UserAPIKeyAuth
+
+
+async def user_api_key_auth(request: Request, api_key: str) -> UserAPIKeyAuth:
+    try:
+        return UserAPIKeyAuth(
+            api_key="best-api-key-ever",
+            user_id="best-user-id-ever",
+            team_id="best-team-id-ever",
+        )
+    except:
+        raise Exception
diff --git a/litellm/proxy/example_config_yaml/pass_through_config.yaml b/litellm/proxy/example_config_yaml/pass_through_config.yaml
new file mode 100644
index 000000000..db9558b3c
--- /dev/null
+++ b/litellm/proxy/example_config_yaml/pass_through_config.yaml
@@ -0,0 +1,9 @@
+model_list:
+ - model_name: fake-openai-endpoint
+   litellm_params:
+     model: openai/fake
+     api_key: fake-key
+     api_base: https://exampleopenaiendpoint-production.up.railway.app/
+general_settings: 
+ master_key: sk-1234 
+ custom_auth: example_config_yaml.custom_auth.user_api_key_auth
\ No newline at end of file
diff --git a/tests/pass_through_tests/test_vertex_ai.py b/tests/pass_through_tests/test_vertex_ai.py
new file mode 100644
index 000000000..10660ddb9
--- /dev/null
+++ b/tests/pass_through_tests/test_vertex_ai.py
@@ -0,0 +1,77 @@
+"""
+Test Vertex AI Pass Through
+
+1. use Credentials client side, Assert SpendLog was created
+"""
+
+import vertexai
+from vertexai.preview.generative_models import GenerativeModel
+import tempfile
+import json
+import os
+from google.oauth2 import service_account
+import google.auth.transport.requests
+
+
+# Path to your service account JSON file
+SERVICE_ACCOUNT_FILE = "path/to/your/service-account.json"
+
+
+def load_vertex_ai_credentials():
+    # Define the path to the vertex_key.json file
+    print("loading vertex ai credentials")
+    filepath = os.path.dirname(os.path.abspath(__file__))
+    vertex_key_path = filepath + "/vertex_key.json"
+
+    # Read the existing content of the file or create an empty dictionary
+    try:
+        with open(vertex_key_path, "r") as file:
+            # Read the file content
+            print("Read vertexai file path")
+            content = file.read()
+
+            # If the file is empty or not valid JSON, create an empty dictionary
+            if not content or not content.strip():
+                service_account_key_data = {}
+            else:
+                # Attempt to load the existing JSON content
+                file.seek(0)
+                service_account_key_data = json.load(file)
+    except FileNotFoundError:
+        # If the file doesn't exist, create an empty dictionary
+        service_account_key_data = {}
+
+    # Update the service_account_key_data with environment variables
+    private_key_id = os.environ.get("VERTEX_AI_PRIVATE_KEY_ID", "")
+    private_key = os.environ.get("VERTEX_AI_PRIVATE_KEY", "")
+    private_key = private_key.replace("\\n", "\n")
+    service_account_key_data["private_key_id"] = private_key_id
+    service_account_key_data["private_key"] = private_key
+
+    # Create a temporary file
+    with tempfile.NamedTemporaryFile(mode="w+", delete=False) as temp_file:
+        # Write the updated content to the temporary files
+        json.dump(service_account_key_data, temp_file, indent=2)
+
+    # Export the temporary file as GOOGLE_APPLICATION_CREDENTIALS
+    os.environ["GOOGLE_APPLICATION_CREDENTIALS"] = os.path.abspath(temp_file.name)
+
+
+LITE_LLM_ENDPOINT = "http://localhost:4000"
+
+
+async def test_basic_vertex_ai_pass_through_with_spendlog():
+
+    vertexai.init(
+        project="adroit-crow-413218",
+        location="us-central1",
+        api_endpoint=f"{LITE_LLM_ENDPOINT}/vertex-ai",
+        api_transport="rest",
+    )
+
+    model = GenerativeModel(model_name="gemini-1.0-pro")
+    response = model.generate_content("hi")
+
+    print("response", response)
+
+    pass
diff --git a/tests/pass_through_tests/vertex_key.json b/tests/pass_through_tests/vertex_key.json
new file mode 100644
index 000000000..e2fd8512b
--- /dev/null
+++ b/tests/pass_through_tests/vertex_key.json
@@ -0,0 +1,13 @@
+{
+  "type": "service_account",
+  "project_id": "adroit-crow-413218",
+  "private_key_id": "",
+  "private_key": "",
+  "client_email": "test-adroit-crow@adroit-crow-413218.iam.gserviceaccount.com",
+  "client_id": "104886546564708740969",
+  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
+  "token_uri": "https://oauth2.googleapis.com/token",
+  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
+  "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/test-adroit-crow%40adroit-crow-413218.iam.gserviceaccount.com",
+  "universe_domain": "googleapis.com"
+}