litellm/docs/my-website/docs/completion/http_handler_config.md

Custom HTTP Handler

Configure custom aiohttp sessions for better performance and control in LiteLLM completions.

Overview

You can now inject custom aiohttp.ClientSession instances into LiteLLM for:

• Custom connection pooling and timeouts
• Corporate proxy and SSL configurations
• Performance optimization
• Request monitoring

Basic Usage

Default (No Changes Required)

import litellm

# Works exactly as before
response = await litellm.acompletion(
    model="gpt-3.5-turbo",
    messages=[{"role": "user", "content": "Hello!"}]
)

Custom Session

import aiohttp
import litellm
from litellm.llms.custom_httpx.aiohttp_handler import BaseLLMAIOHTTPHandler

# Create optimized session
session = aiohttp.ClientSession(
    timeout=aiohttp.ClientTimeout(total=180),
    connector=aiohttp.TCPConnector(limit=300, limit_per_host=75)
)

# Replace global handler
litellm.base_llm_aiohttp_handler = BaseLLMAIOHTTPHandler(client_session=session)

# All completions now use your session
response = await litellm.acompletion(model="gpt-3.5-turbo", messages=[...])

Common Patterns

FastAPI Integration

from contextlib import asynccontextmanager
from fastapi import FastAPI
import aiohttp
import litellm

@asynccontextmanager
async def lifespan(app: FastAPI):
    # Startup
    session = aiohttp.ClientSession(
        timeout=aiohttp.ClientTimeout(total=180),
        connector=aiohttp.TCPConnector(limit=300)
    )
    litellm.base_llm_aiohttp_handler = BaseLLMAIOHTTPHandler(
        client_session=session
    )
    yield
    # Shutdown
    await session.close()

app = FastAPI(lifespan=lifespan)

@app.post("/chat")
async def chat(messages: list[dict]):
    return await litellm.acompletion(model="gpt-3.5-turbo", messages=messages)

Corporate Proxy

import ssl

# Custom SSL context
ssl_context = ssl.create_default_context()
ssl_context.load_cert_chain('cert.pem', 'key.pem')

# Proxy session
session = aiohttp.ClientSession(
    connector=aiohttp.TCPConnector(ssl=ssl_context),
    trust_env=True  # Use environment proxy settings
)

litellm.base_llm_aiohttp_handler = BaseLLMAIOHTTPHandler(client_session=session)

High Performance

# Optimized for high throughput
session = aiohttp.ClientSession(
    timeout=aiohttp.ClientTimeout(total=300),
    connector=aiohttp.TCPConnector(
        limit=1000,             # High connection limit
        limit_per_host=200,     # Per host limit
        ttl_dns_cache=600,      # DNS cache
        keepalive_timeout=60,   # Keep connections alive
        enable_cleanup_closed=True
    )
)

litellm.base_llm_aiohttp_handler = BaseLLMAIOHTTPHandler(client_session=session)

Constructor Options

BaseLLMAIOHTTPHandler(
    client_session=None,    # Custom aiohttp.ClientSession
    transport=None,         # Advanced transport control
    connector=None,         # Custom aiohttp.BaseConnector
)

Resource Management

• User sessions: You manage the lifecycle (call await session.close())
• Auto-created sessions: Automatically cleaned up by the handler
• 100% backward compatible: Existing code works unchanged

Configuration Tips

Development

session = aiohttp.ClientSession(
    timeout=aiohttp.ClientTimeout(total=60),
    connector=aiohttp.TCPConnector(limit=50)
)

Production

session = aiohttp.ClientSession(
    timeout=aiohttp.ClientTimeout(total=300),
    connector=aiohttp.TCPConnector(
        limit=1000,
        limit_per_host=200,
        keepalive_timeout=60
    )
)