✨ Event Hooks for SSO Login

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✨ SSO is free for up to 5 users. After that, an enterprise license is required. Get Started with Enterprise here

Overview

LiteLLM provides two different SSO hooks depending on your authentication setup:

Hook Type	When to Use	What It Does
Custom UI SSO Sign-in Handler	You have an OAuth proxy (oauth2-proxy, Gatekeeper, Vouch, etc.) in front of LiteLLM	Parses user info from request headers and signs user into UI
Custom SSO Handler	You use direct SSO providers (Google, Microsoft, SAML) and want custom post-auth logic	Runs custom code after standard OAuth flow to set user permissions/teams

Quick Decision Guide:

• ✅ Use Custom UI SSO Sign-in Handler if user authentication happens outside LiteLLM (via headers)
• ✅ Use Custom SSO Handler if you want LiteLLM to handle OAuth flow + run custom logic afterward

---

Option 1: Custom UI SSO Sign-in Handler

Use this when you have an OAuth proxy in front of LiteLLM that has already authenticated the user and passes user information via request headers.

How it works

• User lands on Admin UI
• 👉 Your custom SSO sign-in handler is called to parse request headers and return user info
• LiteLLM has retrieved user information from your custom handler
• User signed in to UI

Usage

1. Create a custom UI SSO handler file

This handler parses request headers and returns user information as an OpenID object:

from fastapi import Request
from fastapi_sso.sso.base import OpenID
from litellm.integrations.custom_sso_handler import CustomSSOLoginHandler


class MyCustomSSOLoginHandler(CustomSSOLoginHandler):
    """
    Custom handler for parsing OAuth proxy headers
    
    Use this when you have an OAuth proxy (like oauth2-proxy, Vouch, etc.) 
    in front of LiteLLM that adds user info to request headers
    """
    async def handle_custom_ui_sso_sign_in(
        self,
        request: Request,
    ) -> OpenID:
        # Parse headers from your OAuth proxy
        request_headers = dict(request.headers)
        
        # Extract user info from headers (adjust header names for your proxy)
        user_id = request_headers.get("x-forwarded-user") or request_headers.get("x-user")
        user_email = request_headers.get("x-forwarded-email") or request_headers.get("x-email")
        user_name = request_headers.get("x-forwarded-preferred-username") or request_headers.get("x-preferred-username")
        
        # Return OpenID object with user information
        return OpenID(
            id=user_id or "unknown",
            email=user_email or "unknown@example.com", 
            first_name=user_name or "Unknown",
            last_name="User",
            display_name=user_name or "Unknown User",
            picture=None,
            provider="oauth-proxy",
        )

# Create an instance to be used by LiteLLM
custom_ui_sso_sign_in_handler = MyCustomSSOLoginHandler()

2. Configure in config.yaml

model_list: 
  - model_name: "openai-model"
    litellm_params: 
      model: "gpt-3.5-turbo"

general_settings:
  custom_ui_sso_sign_in_handler: custom_sso_handler.custom_ui_sso_sign_in_handler

litellm_settings:
  drop_params: True
  set_verbose: True

3. Start the proxy

$ litellm --config /path/to/config.yaml 

4. Navigate to the Admin UI

When a user attempts navigating to the LiteLLM Admin UI, the request will be routed to your custom UI SSO sign-in handler.

---

Option 2: Custom SSO Handler (Post-Authentication)

Use this if you want to run your own code after a user signs on to the LiteLLM UI using standard SSO providers (Google, Microsoft, etc.)

How it works

• User lands on Admin UI
• LiteLLM redirects user to your SSO provider (Google, Microsoft, etc.)
• Your SSO provider redirects user back to LiteLLM
• LiteLLM has retrieved user information from your IDP
• 👉 Your custom SSO handler is called and returns an object of type SSOUserDefinedValues
• User signed in to UI

Usage

1. Create a custom SSO handler file

Make sure the response type follows the SSOUserDefinedValues pydantic object. This is used for logging the user into the Admin UI:

from fastapi import Request
from fastapi_sso.sso.base import OpenID

from litellm.proxy._types import LitellmUserRoles, SSOUserDefinedValues
from litellm.proxy.management_endpoints.internal_user_endpoints import (
    new_user,
    user_info,
)
from litellm.proxy.management_endpoints.team_endpoints import add_new_member


async def custom_sso_handler(userIDPInfo: OpenID) -> SSOUserDefinedValues:
    try:
        print("inside custom sso handler")  # noqa
        print(f"userIDPInfo: {userIDPInfo}")  # noqa

        if userIDPInfo.id is None:
            raise ValueError(
                f"No ID found for user. userIDPInfo.id is None {userIDPInfo}"
            )
        

        #################################################
        # Run your custom code / logic here
        # check if user exists in litellm proxy DB
        _user_info = await user_info(user_id=userIDPInfo.id)
        print("_user_info from litellm DB ", _user_info)  # noqa
        #################################################

        return SSOUserDefinedValues(
            models=[],                                      # models user has access to
            user_id=userIDPInfo.id,                         # user id to use in the LiteLLM DB
            user_email=userIDPInfo.email,                   # user email to use in the LiteLLM DB
            user_role=LitellmUserRoles.INTERNAL_USER.value, # role to use for the user 
            max_budget=0.01,                                # Max budget for this UI login Session
            budget_duration="1d",                           # Duration of the budget for this UI login Session, 1d, 2d, 30d ...
        )
    except Exception as e:
        raise Exception("Failed custom auth")

2. Configure in config.yaml

Pass the filepath to the config.yaml.

e.g. if they're both in the same dir - ./config.yaml and ./custom_sso.py, this is what it looks like:

model_list: 
  - model_name: "openai-model"
    litellm_params: 
      model: "gpt-3.5-turbo"

general_settings:
  custom_sso: custom_sso.custom_sso_handler

litellm_settings:
  drop_params: True
  set_verbose: True

3. Start the proxy

$ litellm --config /path/to/config.yaml