[Feature]: Add header support for spend_logs_metadata (#14186)

* fix: allow settings spend_logs_metadata

* fix add_litellm_data_for_backend_llm_call

* fix: add add_litellm_metadata_from_request_headers

* fix add_litellm_metadata_from_request_headers

* test_add_litellm_metadata_from_request_headers

* add_litellm_metadata_from_request_headers

* docs Tracking Spend with custom metadata

* add_litellm_metadata_from_request_headers

* add_litellm_metadata_from_request_headers

docs/my-website/docs/proxy/enterprise.md

@@ -439,6 +439,33 @@ response = client.chat.completions.create(
 
 print(response)
 ```
+
+**Using Headers:**
+
+```python
+import openai
+client = openai.OpenAI(
+    api_key="sk-1234",
+    base_url="http://0.0.0.0:4000"
+)
+
+# Pass spend logs metadata via headers
+response = client.chat.completions.create(
+    model="gpt-3.5-turbo",
+    messages = [
+        {
+            "role": "user",
+            "content": "this is a test request, write a short poem"
+        }
+    ],
+    extra_headers={
+        "x-litellm-spend-logs-metadata": '{"user_id": "12345", "project_id": "proj_abc", "request_type": "chat_completion"}'
+    }
+)
+
+print(response)
+```
+
 </TabItem>
 
 
@@ -478,6 +505,43 @@ async function runOpenAI() {
 // Call the asynchronous function
 runOpenAI();
 ```
+
+**Using Headers:**
+
+```js
+const openai = require('openai');
+
+async function runOpenAI() {
+  const client = new openai.OpenAI({
+    apiKey: 'sk-1234',
+    baseURL: 'http://0.0.0.0:4000'
+  });
+
+  try {
+    const response = await client.chat.completions.create({
+      model: 'gpt-3.5-turbo',
+      messages: [
+        {
+          role: 'user',
+          content: "this is a test request, write a short poem"
+        },
+      ]
+    }, {
+      headers: {
+        'x-litellm-spend-logs-metadata': '{"user_id": "12345", "project_id": "proj_abc", "request_type": "chat_completion"}'
+      }
+    });
+    console.log(response);
+  } catch (error) {
+    console.log("got this exception from server");
+    console.error(error);
+  }
+}
+
+// Call the asynchronous function
+runOpenAI();
+```
+
 </TabItem>
 
 <TabItem value="Curl" label="Curl Request">
@@ -502,6 +566,29 @@ curl --location 'http://0.0.0.0:4000/chat/completions' \
     }
 }'
 ```
+
+</TabItem>
+
+<TabItem value="headers" label="Using Headers">
+
+Pass `x-litellm-spend-logs-metadata` as a request header with JSON string
+
+```shell
+curl --location 'http://0.0.0.0:4000/chat/completions' \
+    --header 'Content-Type: application/json' \
+    --header 'Authorization: Bearer sk-1234' \
+    --header 'x-litellm-spend-logs-metadata: {"user_id": "12345", "project_id": "proj_abc", "request_type": "chat_completion"}' \
+    --data '{
+    "model": "gpt-3.5-turbo",
+    "messages": [
+        {
+        "role": "user",
+        "content": "what llm are you"
+        }
+    ]
+}'
+```
+
 </TabItem>
 <TabItem value="langchain" label="Langchain">
 

docs/my-website/docs/proxy/request_headers.md

@@ -14,6 +14,8 @@ Special headers that are supported by LiteLLM.
 
 `x-litellm-num-retries`: Optional[int]: The number of retries for the request.
 
+`x-litellm-spend-logs-metadata`: Optional[str]: JSON string containing custom metadata to include in spend logs. Example: `{"user_id": "12345", "project_id": "proj_abc", "request_type": "chat_completion"}`. [Learn More](./logging#tracking-spend-with-custom-metadata)
+
 ## Anthropic Headers
 
 `anthropic-version` Optional[str]: The version of the Anthropic API to use.  

litellm/proxy/_types.py

@@ -2908,6 +2908,12 @@ class LitellmDataForBackendLLMCall(TypedDict, total=False):
     user: Optional[str]
     num_retries: Optional[int]
 
+class LitellmMetadataFromRequestHeaders(TypedDict, total=False):
+    """
+    Headers a user can pass that will get added to litellm metadata for the request
+    """
+    spend_logs_metadata: Optional[dict]
+
 
 class JWTKeyItem(TypedDict, total=False):
     kid: str

litellm/proxy/litellm_pre_call_utils.py

@@ -291,6 +291,17 @@ class LiteLLMProxyRequestSetup:
         if num_retries_header is not None:
             return int(num_retries_header)
         return None
+    
+    @staticmethod
+    def _get_spend_logs_metadata_from_request_headers(headers: dict) -> Optional[dict]:
+        """
+        Get the `spend_logs_metadata` from the request headers.
+        """
+        from litellm.litellm_core_utils.safe_json_loads import safe_json_loads
+        spend_logs_metadata_header = headers.get("x-litellm-spend-logs-metadata", None)
+        if spend_logs_metadata_header is not None:
+            return safe_json_loads(spend_logs_metadata_header)
+        return None
 
     @staticmethod
     def _get_forwardable_headers(
@@ -459,6 +470,30 @@ class LiteLLMProxyRequestSetup:
             data["num_retries"] = num_retries
 
         return data
+    
+    @staticmethod
+    def add_litellm_metadata_from_request_headers(
+        headers: dict,
+        data: dict,
+        _metadata_variable_name: str,
+    ) -> dict:
+        """
+        Add litellm metadata from request headers
+
+        Relevant issue: https://github.com/BerriAI/litellm/issues/14008
+        """
+        from litellm.proxy._types import LitellmMetadataFromRequestHeaders
+        metadata_from_headers = LitellmMetadataFromRequestHeaders()
+        spend_logs_metadata = LiteLLMProxyRequestSetup._get_spend_logs_metadata_from_request_headers(headers)
+        if spend_logs_metadata is not None:
+            metadata_from_headers["spend_logs_metadata"] = spend_logs_metadata
+        
+        #########################################################################################
+        # Finally update the requests metadata with the `metadata_from_headers`
+        #########################################################################################
+        if isinstance(data[_metadata_variable_name], dict):
+            data[_metadata_variable_name].update(metadata_from_headers)
+        return data
 
     @staticmethod
     def get_sanitized_user_information_from_key(
@@ -643,6 +678,10 @@ async def add_litellm_data_to_request(  # noqa: PLR0915
     from litellm.types.proxy.litellm_pre_call_utils import SecretFields
 
     safe_add_api_version_from_query_params(data, request)
+    _metadata_variable_name = _get_metadata_variable_name(request)
+    if data.get(_metadata_variable_name, None) is None:
+        data[_metadata_variable_name] = {}
+
 
     _headers = clean_headers(
         request.headers,
@@ -661,6 +700,14 @@ async def add_litellm_data_to_request(  # noqa: PLR0915
         )
     )
 
+    data.update(
+        LiteLLMProxyRequestSetup.add_litellm_metadata_from_request_headers(
+            headers=_headers,
+            data=data,
+            _metadata_variable_name=_metadata_variable_name,
+        )
+    )
+
     # check for forwardable headers
     data = LiteLLMProxyRequestSetup.add_headers_to_llm_call_by_model_group(
         data=data, headers=_headers, user_api_key_dict=user_api_key_dict
@@ -711,11 +758,6 @@ async def add_litellm_data_to_request(  # noqa: PLR0915
 
     verbose_proxy_logger.debug("receiving data: %s", data)
 
-    _metadata_variable_name = _get_metadata_variable_name(request)
-
-    if data.get(_metadata_variable_name, None) is None:
-        data[_metadata_variable_name] = {}
-
     # Parse metadata if it's a string (e.g., from multipart/form-data)
     if "metadata" in data and data["metadata"] is not None:
         if isinstance(data["metadata"], str):

tests/test_litellm/proxy/test_litellm_pre_call_utils.py

@@ -8,6 +8,7 @@ from unittest.mock import MagicMock, patch
 import pytest
 from fastapi import Request
 
+import litellm
 from litellm.proxy._types import TeamCallbackMetadata, UserAPIKeyAuth
 from litellm.proxy.litellm_pre_call_utils import (
     KeyAndTeamLoggingSettings,
@@ -935,3 +936,126 @@ def test_add_headers_to_llm_call_by_model_group_existing_headers_in_data():
     finally:
         # Restore original model_group_settings
         litellm.model_group_settings = original_model_group_settings
+
+import json
+import time
+from typing import Optional
+from unittest.mock import AsyncMock
+
+from fastapi.responses import Response
+
+from litellm.integrations.custom_logger import CustomLogger
+from litellm.proxy.common_request_processing import ProxyBaseLLMRequestProcessing
+from litellm.proxy.utils import ProxyLogging
+from litellm.types.utils import StandardLoggingPayload
+
+
+class TestCustomLogger(CustomLogger):
+    def __init__(self):
+        self.standard_logging_object: Optional[StandardLoggingPayload] = None
+        super().__init__()
+        
+    async def async_log_success_event(self, kwargs, response_obj, start_time, end_time):
+        print(f"SUCCESS CALLBACK CALLED! kwargs keys: {list(kwargs.keys())}")
+        self.standard_logging_object = kwargs.get("standard_logging_object")
+        print(f"Captured standard_logging_object: {self.standard_logging_object}")
+        
+    async def async_log_failure_event(self, kwargs, response_obj, start_time, end_time):
+        print(f"FAILURE CALLBACK CALLED! kwargs keys: {list(kwargs.keys())}")
+
+@pytest.mark.asyncio
+async def test_add_litellm_metadata_from_request_headers():
+    """
+    Test that add_litellm_metadata_from_request_headers properly adds litellm metadata from request headers,
+    makes an LLM request using base_process_llm_request, sleeps for 3 seconds, and checks standard_logging_payload has spend_logs_metadata from headers
+
+    Relevant issue: https://github.com/BerriAI/litellm/issues/14008
+    """
+    # Set up test logger
+    litellm._turn_on_debug()
+    test_logger = TestCustomLogger()
+    litellm.callbacks = [test_logger]
+
+    # Prepare test data (ensure no streaming, add mock_response and api_key to route to litellm.acompletion)
+    headers = {"x-litellm-spend-logs-metadata": '{"user_id": "12345", "project_id": "proj_abc", "request_type": "chat_completion", "timestamp": "2025-09-02T10:30:00Z"}'}
+    data = {"model": "gpt-4", "messages": [{"role": "user", "content": "Hello"}], "stream": False, "mock_response": "Hi", "api_key": "fake-key"}
+    
+    # Create mock request with headers
+    mock_request = MagicMock(spec=Request)
+    mock_request.headers = headers
+    mock_request.url.path = "/chat/completions"
+    
+    # Create mock response
+    mock_fastapi_response = MagicMock(spec=Response)
+    
+    # Create mock user API key dict
+    mock_user_api_key_dict = UserAPIKeyAuth(
+        api_key="test-key",
+        user_id="test-user",
+        org_id="test-org"
+    )
+    
+    # Create mock proxy logging object
+    mock_proxy_logging_obj = MagicMock(spec=ProxyLogging)
+    
+    # Create async functions for the hooks
+    async def mock_during_call_hook(*args, **kwargs):
+        return None
+        
+    async def mock_pre_call_hook(*args, **kwargs):
+        return data
+        
+    async def mock_post_call_success_hook(*args, **kwargs):
+        # Return the response unchanged
+        return kwargs.get('response', args[2] if len(args) > 2 else None)
+        
+    mock_proxy_logging_obj.during_call_hook = mock_during_call_hook
+    mock_proxy_logging_obj.pre_call_hook = mock_pre_call_hook
+    mock_proxy_logging_obj.post_call_success_hook = mock_post_call_success_hook
+    
+    # Create mock proxy config
+    mock_proxy_config = MagicMock()
+    
+    # Create mock general settings
+    general_settings = {}
+    
+    # Create mock select_data_generator with correct signature
+    def mock_select_data_generator(response=None, user_api_key_dict=None, request_data=None):
+        async def mock_generator():
+            yield "data: " + json.dumps({"choices": [{"delta": {"content": "Hello"}}]}) + "\n\n"
+            yield "data: [DONE]\n\n"
+        return mock_generator()
+    
+    # Create the processor
+    processor = ProxyBaseLLMRequestProcessing(data=data)
+    
+    # Call base_process_llm_request (it will use the mock_response="Hi" parameter)
+    result = await processor.base_process_llm_request(
+        request=mock_request,
+        fastapi_response=mock_fastapi_response,
+        user_api_key_dict=mock_user_api_key_dict,
+        route_type="acompletion",
+        proxy_logging_obj=mock_proxy_logging_obj,
+        general_settings=general_settings,
+        proxy_config=mock_proxy_config,
+        select_data_generator=mock_select_data_generator,
+        llm_router=None,
+        model="gpt-4",
+        is_streaming_request=False
+    )
+    
+    # Sleep for 3 seconds to allow logging to complete
+    await asyncio.sleep(3)
+    
+    # Check if standard_logging_object was set
+    assert test_logger.standard_logging_object is not None, "standard_logging_object should be populated after LLM request"
+    
+    # Verify the logging object contains expected metadata
+    standard_logging_obj = test_logger.standard_logging_object
+
+    print(f"Standard logging object captured: {json.dumps(standard_logging_obj, indent=4, default=str)}")
+
+    SPEND_LOGS_METADATA = standard_logging_obj["metadata"]["spend_logs_metadata"]
+    assert SPEND_LOGS_METADATA == dict(json.loads(headers["x-litellm-spend-logs-metadata"])), "spend_logs_metadata should be the same as the headers"
+
+