litellm/litellm/passthrough
devin-ai-integration[bot] 1fd04abb92
fix(responses): fall back on pre-output stream drops, fail truncated streams, honor request_timeout (#43133)
* fix(responses): fall back on pre-output stream drops, fail truncated streams, honor request_timeout

A native /v1/responses stream that drops before any output item now raises
the router's fallback-eligible MidStreamFallbackError, so configured
fallbacks retry the original input. A stream that ends with a clean EOF or
a [DONE] marker but no response.completed, response.incomplete or
response.failed event now raises litellm.APIConnectionError instead of
ending as if it had completed: fallback-eligible before any output, an
explicit error after partial output. The sync iterator mirrors every branch.

resolve_llm_passthrough_timeout now consults an explicitly set
litellm_settings.request_timeout right after the router timeout and before
general_settings.pass_through_request_timeout, so the router's native
responses path honors it.

* test(responses): give the normal-completion stream tests a terminal event

---------

Co-authored-by: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
2026-09-25 14:32:41 -07:00
..
__init__.py refactor(lint): apply every safe ruff autofix and zero 28 strict-rule budgets 2026-08-01 15:43:29 -07:00
main.py refactor: daily fresh tech debt cleanup, rolling PR (#42710) 2026-09-24 04:17:23 -07:00
README.md build(VLLM-Passthrough-with-loadbalancing-support-(enables-using-model-list-for-VLLM-/classify-endpoint)): Closes #11205 2025-05-31 09:00:04 -07:00
timeout_utils.py fix(responses): fall back on pre-output stream drops, fail truncated streams, honor request_timeout (#43133) 2026-09-25 14:32:41 -07:00
utils.py feat(proxy): add Azure AI Speech pass-through route 2026-09-17 03:03:19 +00:00

This makes it easier to pass through requests to the LLM APIs.

E.g. Route to VLLM's /classify endpoint:

SDK (Basic)

import litellm


response = litellm.llm_passthrough_route(
    model="hosted_vllm/papluca/xlm-roberta-base-language-detection",
    method="POST",
    endpoint="classify",
    api_base="http://localhost:8090",
    api_key=None,
    json={
        "model": "swapped-for-litellm-model",
        "input": "Hello, world!",
    }
)

print(response)

SDK (Router)

import asyncio
from litellm import Router

router = Router(
    model_list=[
        {
            "model_name": "roberta-base-language-detection",
            "litellm_params": {
                "model": "hosted_vllm/papluca/xlm-roberta-base-language-detection",
                "api_base": "http://localhost:8090", 
            }
        }
    ]
)

request_data = {
    "model": "roberta-base-language-detection",
    "method": "POST",
    "endpoint": "classify",
    "api_base": "http://localhost:8090",
    "api_key": None,
    "json": {
        "model": "roberta-base-language-detection",
        "input": "Hello, world!",
    }
}

async def main():
    response = await router.allm_passthrough_route(**request_data)
    print(response)

if __name__ == "__main__":
    asyncio.run(main())

PROXY

  1. Setup config.yaml
model_list:
  - model_name: roberta-base-language-detection
    litellm_params:
      model: hosted_vllm/papluca/xlm-roberta-base-language-detection
      api_base: http://localhost:8090
  1. Run the proxy
litellm proxy --config config.yaml

# RUNNING on http://localhost:4000
  1. Use the proxy
curl -X POST http://localhost:4000/vllm/classify \
-H "Content-Type: application/json" \
-H "Authorization: Bearer <your-api-key>" \
-d '{"model": "roberta-base-language-detection", "input": "Hello, world!"}' \

How to add a provider for passthrough

See VLLMModelInfo for an example.

  1. Inherit from BaseModelInfo
from litellm.llms.base_llm.base_utils import BaseLLMModelInfo

class VLLMModelInfo(BaseLLMModelInfo):
    pass
  1. Register the provider in the ProviderConfigManager.get_provider_model_info
from litellm.utils import ProviderConfigManager
from litellm.types.utils import LlmProviders

provider_config = ProviderConfigManager.get_provider_model_info(
    model="my-test-model", provider=LlmProviders.VLLM
)

print(provider_config)