diff --git a/.circleci/config.yml b/.circleci/config.yml
index 04f2a30c51..0cbd51477c 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1982,6 +1982,37 @@ jobs:
       - run:
           name: Wait for app to be ready
           command: dockerize -wait http://localhost:4000 -timeout 5m
+      # Add Ruby installation and testing before the existing Node.js and Python tests
+      - run:
+          name: Install Ruby and Bundler
+          command: |
+            # Import GPG keys first
+            gpg --keyserver hkp://keyserver.ubuntu.com --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 7D2BAF1CF37B13E2069D6956105BD0E739499BDB || {
+              curl -sSL https://rvm.io/mpapis.asc | gpg --import -
+              curl -sSL https://rvm.io/pkuczynski.asc | gpg --import -
+            }
+            
+            # Install Ruby version manager (RVM)
+            curl -sSL https://get.rvm.io | bash -s stable
+            
+            # Source RVM from the correct location
+            source $HOME/.rvm/scripts/rvm
+            
+            # Install Ruby 3.2.2
+            rvm install 3.2.2
+            rvm use 3.2.2 --default
+            
+            # Install latest Bundler
+            gem install bundler
+
+      - run:
+          name: Run Ruby tests
+          command: |
+            source $HOME/.rvm/scripts/rvm
+            cd tests/pass_through_tests/ruby_passthrough_tests
+            bundle install
+            bundle exec rspec
+          no_output_timeout: 30m
       # New steps to run Node.js test
       - run:
           name: Install Node.js
diff --git a/litellm/proxy/pass_through_endpoints/llm_passthrough_endpoints.py b/litellm/proxy/pass_through_endpoints/llm_passthrough_endpoints.py
index a2ca47406f..4724c7f9d1 100644
--- a/litellm/proxy/pass_through_endpoints/llm_passthrough_endpoints.py
+++ b/litellm/proxy/pass_through_endpoints/llm_passthrough_endpoints.py
@@ -398,7 +398,7 @@ async def azure_proxy_route(
         )
     # Add or update query parameters
     azure_api_key = passthrough_endpoint_router.get_credentials(
-        custom_llm_provider="azure",
+        custom_llm_provider=litellm.LlmProviders.AZURE.value,
         region_name=None,
     )
     if azure_api_key is None:
@@ -413,6 +413,7 @@ async def azure_proxy_route(
         user_api_key_dict=user_api_key_dict,
         base_target_url=base_target_url,
         api_key=azure_api_key,
+        custom_llm_provider=litellm.LlmProviders.AZURE,
     )
 
 
@@ -435,7 +436,7 @@ async def openai_proxy_route(
     base_target_url = "https://api.openai.com/"
     # Add or update query parameters
     openai_api_key = passthrough_endpoint_router.get_credentials(
-        custom_llm_provider="openai",
+        custom_llm_provider=litellm.LlmProviders.OPENAI.value,
         region_name=None,
     )
     if openai_api_key is None:
@@ -450,6 +451,7 @@ async def openai_proxy_route(
         user_api_key_dict=user_api_key_dict,
         base_target_url=base_target_url,
         api_key=openai_api_key,
+        custom_llm_provider=litellm.LlmProviders.OPENAI,
     )
 
 
@@ -462,24 +464,19 @@ class BaseOpenAIPassThroughHandler:
         user_api_key_dict: UserAPIKeyAuth,
         base_target_url: str,
         api_key: str,
+        custom_llm_provider: litellm.LlmProviders,
     ):
         encoded_endpoint = httpx.URL(endpoint).path
-
         # Ensure endpoint starts with '/' for proper URL construction
         if not encoded_endpoint.startswith("/"):
             encoded_endpoint = "/" + encoded_endpoint
 
-        # Ensure base_target_url is properly formatted for OpenAI
-        base_target_url = (
-            BaseOpenAIPassThroughHandler._append_v1_to_openai_passthrough_url(
-                base_target_url
-            )
-        )
-
         # Construct the full target URL by properly joining the base URL and endpoint path
         base_url = httpx.URL(base_target_url)
         updated_url = BaseOpenAIPassThroughHandler._join_url_paths(
-            base_url, encoded_endpoint
+            base_url=base_url,
+            path=encoded_endpoint,
+            custom_llm_provider=custom_llm_provider,
         )
 
         ## check for streaming
@@ -505,21 +502,15 @@ class BaseOpenAIPassThroughHandler:
 
         return received_value
 
-    @staticmethod
-    def _append_v1_to_openai_passthrough_url(base_url: str) -> str:
-        """
-        Appends the /v1 path to the OpenAI base URL if it's the OpenAI API URL
-        """
-        if base_url.rstrip("/") == "https://api.openai.com":
-            return "https://api.openai.com/v1"
-        return base_url
-
     @staticmethod
     def _append_openai_beta_header(headers: dict, request: Request) -> dict:
         """
         Appends the OpenAI-Beta header to the headers if the request is an OpenAI Assistants API request
         """
-        if RouteChecks._is_assistants_api_request(request) is True:
+        if (
+            RouteChecks._is_assistants_api_request(request) is True
+            and "OpenAI-Beta" not in headers
+        ):
             headers["OpenAI-Beta"] = "assistants=v2"
         return headers
 
@@ -535,17 +526,31 @@ class BaseOpenAIPassThroughHandler:
         )
 
     @staticmethod
-    def _join_url_paths(base_url: httpx.URL, path: str) -> httpx.URL:
+    def _join_url_paths(
+        base_url: httpx.URL, path: str, custom_llm_provider: litellm.LlmProviders
+    ) -> str:
         """
         Properly joins a base URL with a path, preserving any existing path in the base URL.
         """
+        # Join paths correctly by removing trailing/leading slashes as needed
         if not base_url.path or base_url.path == "/":
             # If base URL has no path, just use the new path
-            return base_url.copy_with(path=path)
+            joined_path_str = str(base_url.copy_with(path=path))
+        else:
+            # Otherwise, combine the paths
+            base_path = base_url.path.rstrip("/")
+            clean_path = path.lstrip("/")
+            full_path = f"{base_path}/{clean_path}"
+            joined_path_str = str(base_url.copy_with(path=full_path))
 
-        # Join paths correctly by removing trailing/leading slashes as needed
-        base_path = base_url.path.rstrip("/")
-        clean_path = path.lstrip("/")
-        full_path = f"{base_path}/{clean_path}"
+        # Apply OpenAI-specific path handling for both branches
+        if (
+            custom_llm_provider == litellm.LlmProviders.OPENAI
+            and "/v1/" not in joined_path_str
+        ):
+            # Insert v1 after api.openai.com for OpenAI requests
+            joined_path_str = joined_path_str.replace(
+                "api.openai.com/", "api.openai.com/v1/"
+            )
 
-        return base_url.copy_with(path=full_path)
+        return joined_path_str
diff --git a/tests/litellm/proxy/pass_through_endpoints/test_llm_pass_through_endpoints.py b/tests/litellm/proxy/pass_through_endpoints/test_llm_pass_through_endpoints.py
index 82a1b6ecfd..2f5ce85de7 100644
--- a/tests/litellm/proxy/pass_through_endpoints/test_llm_pass_through_endpoints.py
+++ b/tests/litellm/proxy/pass_through_endpoints/test_llm_pass_through_endpoints.py
@@ -12,6 +12,7 @@ sys.path.insert(
     0, os.path.abspath("../../../..")
 )  # Adds the parent directory to the system path
 
+import litellm
 from litellm.proxy.pass_through_endpoints.llm_passthrough_endpoints import (
     BaseOpenAIPassThroughHandler,
     RouteChecks,
@@ -21,60 +22,42 @@ from litellm.proxy.pass_through_endpoints.llm_passthrough_endpoints import (
 
 class TestBaseOpenAIPassThroughHandler:
 
-    def test_append_v1_to_openai_passthrough_url(self):
-        print("\nTesting _append_v1_to_openai_passthrough_url method...")
-
-        # Test with OpenAI API URL
-        result1 = BaseOpenAIPassThroughHandler._append_v1_to_openai_passthrough_url(
-            "https://api.openai.com"
-        )
-        print(f"OpenAI URL: 'https://api.openai.com' → '{result1}'")
-        assert result1 == "https://api.openai.com/v1"
-
-        # Test with OpenAI API URL with trailing slash
-        result2 = BaseOpenAIPassThroughHandler._append_v1_to_openai_passthrough_url(
-            "https://api.openai.com/"
-        )
-        print(
-            f"OpenAI URL with trailing slash: 'https://api.openai.com/' → '{result2}'"
-        )
-        assert result2 == "https://api.openai.com/v1"
-
-        # Test with non-OpenAI URL
-        result3 = BaseOpenAIPassThroughHandler._append_v1_to_openai_passthrough_url(
-            "https://api.anthropic.com"
-        )
-        print(f"Non-OpenAI URL: 'https://api.anthropic.com' → '{result3}'")
-        assert result3 == "https://api.anthropic.com"
-
     def test_join_url_paths(self):
         print("\nTesting _join_url_paths method...")
 
         # Test joining base URL with no path and a path
         base_url = httpx.URL("https://api.example.com")
         path = "/v1/chat/completions"
-        result = BaseOpenAIPassThroughHandler._join_url_paths(base_url, path)
+        result = BaseOpenAIPassThroughHandler._join_url_paths(
+            base_url, path, litellm.LlmProviders.OPENAI.value
+        )
         print(f"Base URL with no path: '{base_url}' + '{path}' → '{result}'")
         assert str(result) == "https://api.example.com/v1/chat/completions"
 
         # Test joining base URL with path and another path
         base_url = httpx.URL("https://api.example.com/v1")
         path = "/chat/completions"
-        result = BaseOpenAIPassThroughHandler._join_url_paths(base_url, path)
+        result = BaseOpenAIPassThroughHandler._join_url_paths(
+            base_url, path, litellm.LlmProviders.OPENAI.value
+        )
         print(f"Base URL with path: '{base_url}' + '{path}' → '{result}'")
         assert str(result) == "https://api.example.com/v1/chat/completions"
 
         # Test with path not starting with slash
         base_url = httpx.URL("https://api.example.com/v1")
         path = "chat/completions"
-        result = BaseOpenAIPassThroughHandler._join_url_paths(base_url, path)
+        result = BaseOpenAIPassThroughHandler._join_url_paths(
+            base_url, path, litellm.LlmProviders.OPENAI.value
+        )
         print(f"Path without leading slash: '{base_url}' + '{path}' → '{result}'")
         assert str(result) == "https://api.example.com/v1/chat/completions"
 
         # Test with base URL having trailing slash
         base_url = httpx.URL("https://api.example.com/v1/")
         path = "/chat/completions"
-        result = BaseOpenAIPassThroughHandler._join_url_paths(base_url, path)
+        result = BaseOpenAIPassThroughHandler._join_url_paths(
+            base_url, path, litellm.LlmProviders.OPENAI.value
+        )
         print(f"Base URL with trailing slash: '{base_url}' + '{path}' → '{result}'")
         assert str(result) == "https://api.example.com/v1/chat/completions"
 
@@ -170,6 +153,7 @@ class TestBaseOpenAIPassThroughHandler:
             user_api_key_dict=mock_user_api_key_dict,
             base_target_url="https://api.openai.com",
             api_key="test_api_key",
+            custom_llm_provider=litellm.LlmProviders.OPENAI.value,
         )
 
         # Verify the result
diff --git a/tests/pass_through_tests/ruby_passthrough_tests/Gemfile b/tests/pass_through_tests/ruby_passthrough_tests/Gemfile
new file mode 100644
index 0000000000..56860496b2
--- /dev/null
+++ b/tests/pass_through_tests/ruby_passthrough_tests/Gemfile
@@ -0,0 +1,4 @@
+source 'https://rubygems.org'
+
+gem 'rspec'
+gem 'ruby-openai'
\ No newline at end of file
diff --git a/tests/pass_through_tests/ruby_passthrough_tests/Gemfile.lock b/tests/pass_through_tests/ruby_passthrough_tests/Gemfile.lock
new file mode 100644
index 0000000000..2072798ccf
--- /dev/null
+++ b/tests/pass_through_tests/ruby_passthrough_tests/Gemfile.lock
@@ -0,0 +1,42 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    base64 (0.2.0)
+    diff-lcs (1.6.0)
+    event_stream_parser (1.0.0)
+    faraday (2.8.1)
+      base64
+      faraday-net_http (>= 2.0, < 3.1)
+      ruby2_keywords (>= 0.0.4)
+    faraday-multipart (1.1.0)
+      multipart-post (~> 2.0)
+    faraday-net_http (3.0.2)
+    multipart-post (2.4.1)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.3)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.3)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.2)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.2)
+    ruby-openai (7.4.0)
+      event_stream_parser (>= 0.3.0, < 2.0.0)
+      faraday (>= 1)
+      faraday-multipart (>= 1)
+    ruby2_keywords (0.0.5)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  rspec
+  ruby-openai
+
+BUNDLED WITH
+   2.6.5
diff --git a/tests/pass_through_tests/ruby_passthrough_tests/spec/openai_assistants_passthrough_spec.rb b/tests/pass_through_tests/ruby_passthrough_tests/spec/openai_assistants_passthrough_spec.rb
new file mode 100644
index 0000000000..1cfaeb5e20
--- /dev/null
+++ b/tests/pass_through_tests/ruby_passthrough_tests/spec/openai_assistants_passthrough_spec.rb
@@ -0,0 +1,95 @@
+require 'openai'
+require 'rspec'
+
+RSpec.describe 'OpenAI Assistants Passthrough' do
+  let(:client) do
+    OpenAI::Client.new(
+      access_token: "sk-1234",
+      uri_base: "http://0.0.0.0:4000/openai"
+    )
+  end
+
+
+  it 'performs basic assistant operations' do
+    assistant = client.assistants.create(
+      parameters: {
+        name: "Math Tutor",
+        instructions: "You are a personal math tutor. Write and run code to answer math questions.",
+        tools: [{ type: "code_interpreter" }],
+        model: "gpt-4o"
+      }
+    )
+    expect(assistant).to include('id')
+    expect(assistant['name']).to eq("Math Tutor")
+
+    assistants_list = client.assistants.list
+    expect(assistants_list['data']).to be_an(Array)
+    expect(assistants_list['data']).to include(include('id' => assistant['id']))
+
+    retrieved_assistant = client.assistants.retrieve(id: assistant['id'])
+    expect(retrieved_assistant).to eq(assistant)
+
+    deleted_assistant = client.assistants.delete(id: assistant['id'])
+    expect(deleted_assistant['deleted']).to be true
+    expect(deleted_assistant['id']).to eq(assistant['id'])
+  end
+
+  it 'performs streaming assistant operations' do
+    puts "\n=== Starting Streaming Assistant Test ==="
+    
+    assistant = client.assistants.create(
+      parameters: {
+        name: "Math Tutor",
+        instructions: "You are a personal math tutor. Write and run code to answer math questions.",
+        tools: [{ type: "code_interpreter" }],
+        model: "gpt-4o"
+      }
+    )
+    puts "Created assistant: #{assistant['id']}"
+    expect(assistant).to include('id')
+
+    thread = client.threads.create
+    puts "Created thread: #{thread['id']}"
+    expect(thread).to include('id')
+
+    message = client.messages.create(
+      thread_id: thread['id'],
+      parameters: {
+        role: "user",
+        content: "I need to solve the equation `3x + 11 = 14`. Can you help me?"
+      }
+    )
+    puts "Created message: #{message['id']}"
+    puts "User question: #{message['content']}"
+    expect(message).to include('id')
+    expect(message['role']).to eq('user')
+
+    puts "\nStarting streaming response:"
+    puts "------------------------"
+    run = client.runs.create(
+      thread_id: thread['id'],
+      parameters: {
+        assistant_id: assistant['id'],
+        max_prompt_tokens: 256,
+        max_completion_tokens: 16,
+        stream: proc do |chunk, _bytesize|
+          puts "Received chunk: #{chunk.inspect}"  # Debug: Print raw chunk
+          if chunk["object"] == "thread.message.delta"
+            content = chunk.dig("delta", "content")
+            puts "Content: #{content.inspect}"  # Debug: Print content structure
+            if content && content[0] && content[0]["text"]
+              print content[0]["text"]["value"]
+              $stdout.flush  # Ensure output is printed immediately
+            end
+          end
+        end
+      }
+    )
+    puts "\n------------------------"
+    puts "Run completed: #{run['id']}"
+    expect(run).not_to be_nil
+  ensure
+    client.assistants.delete(id: assistant['id']) if assistant && assistant['id']
+    client.threads.delete(id: thread['id']) if thread && thread['id']
+  end
+end 
\ No newline at end of file