How to build OIDC enterprise SSO with Python

For our new friends:

Logto is an Auth0 alternative designed for modern apps and SaaS products. It offers both Cloud and Open-source services to help you quickly launch your identity and management (IAM) system. Enjoy authentication, authorization, and multi-tenant management all in one.

We recommend starting with a free development tenant on Logto Cloud. This allows you to explore all the features easily.

In this article, we will go through the steps to quickly build the OIDC enterprise SSO sign-in experience (user authentication) with Python and Logto.

Prerequisites

A running Logto instance. Check out the introduction page to get started.
Basic knowledge of Python.
A usable OIDC enterprise SSO account.

Create an application in Logto

Logto is based on OpenID Connect (OIDC) authentication and OAuth 2.0 authorization. It supports federated identity management across multiple applications, commonly called Single Sign-On (SSO).

To create your Traditional web application, simply follow these steps:

Open the Logto Console. In the "Get started" section, click the "View all" link to open the application frameworks list. Alternatively, you can navigate to Logto Console > Applications, and click the "Create application" button.
In the opening modal, click the "Traditional web" section or filter all the available "Traditional web" frameworks using the quick filter checkboxes on the left. Click the "Flask" framework card to start creating your application.
Enter the application name, e.g., "Bookstore," and click "Create application".

🎉 Ta-da! You just created your first application in Logto. You'll see a congrats page which includes a detailed integration guide. Follow the guide to see what the experience will be in your application.

Integrate Flask SDK

tip:

The example uses Flask, but the concepts are the same for other frameworks.
The Python sample project is available on our Python SDK repo.
Logto SDK leverages coroutines, remember to use await when calling async functions.

Installation

Execute in the project root directory:

pip install logto # or `poetry add logto` or whatever you use

Init LogtoClient

First, create a Logto config:

client.py
from logto import LogtoClient, LogtoConfig

client = LogtoClient(
    LogtoConfig(
        endpoint="https://you-logto-endpoint.app",  # Replace with your Logto endpoint
        appId="replace-with-your-app-id",
        appSecret="replace-with-your-app-secret",
    ),
)

tip:

You can find and copy "App Secret" from application details page in Admin Console:

Also replace the default memory storage with a persistent storage, for example:

client.py
from logto import LogtoClient, LogtoConfig, Storage
from flask import session
from typing import Union

class SessionStorage(Storage):
    def get(self, key: str) -> Union[str, None]:
        return session.get(key, None)

    def set(self, key: str, value: Union[str, None]) -> None:
        session[key] = value

    def delete(self, key: str) -> None:
        session.pop(key, None)

client = LogtoClient(
    LogtoConfig(...),
    storage=SessionStorage(),
)

See Storage for more details.

In your web application, add a route to properly handle the sign-in request from users. Let's use /sign-in as an example:

flask.py
@app.route("/sign-in")
async def sign_in():
  # Get the sign-in URL and redirect the user to it
  return redirect(await client.signIn(
      redirectUri="http://localhost:3000/callback",
  ))

Replace http://localhost:3000/callback with the callback URL you set in your Logto Console for this application.

If you want to show the sign-up page on the first screen, you can set interactionMode to signUp:

flask.py
@app.route("/sign-in")
async def sign_in():
  return redirect(await client.signIn(
      redirectUri="http://localhost:3000/callback",
      interactionMode="signUp", # Show the sign-up page on the first screen
  ))

Now, whenever your users visit http://localhost:3000/sign-in, it will start a new sign-in attempt and redirect the user to the Logto sign-in page.

Note Creating a sign-in route isn't the only way to start a sign-in attempt. You can always use the signIn method to get the sign-in URL and redirect the user to it.

After the user makes a signing-out request, Logto will clear all user authentication information in the session.

To clean up the Python session and Logto session, a sign-out route can be implemented as follows:

flask.py
@app.route("/sign-out")
async def sign_out():
  return redirect(
      # Redirect the user to the home page after a successful sign-out
      await client.signOut(postLogoutRedirectUri="http://localhost:3000/")
  )

Handle authentication status

In Logto SDK, we can use client.isAuthenticated() to check the authentication status, if the user is signed in, the value will be true, otherwise, the value will be false.

Here we also implement a simple home page for demonstration:

If the user is not signed in, show a sign-in button;
If the user is signed in, show a sign-out button.

@app.route("/")
async def home():
    if client.isAuthenticated() is False:
        return "Not authenticated <a href='/sign-in'>Sign in</a>"
    return "Authenticated <a href='/sign-out'>Sign out</a>"

Checkpoint: Test your application

Now, you can test your application:

Run your application, you will see the sign-in button.
Click the sign-in button, the SDK will init the sign-in process and redirect you to the Logto sign-in page.
After you signed in, you will be redirected back to your application and see the sign-out button.
Click the sign-out button to clear token storage and sign out.

Add OIDC enterprise SSO connector

To simplify access management and gain enterprise-level safeguards for your big clients, connect with Flask as a federated identity provider. The Logto enterprise SSO connector helps you establish this connection in minutes by allowing several parameter inputs.

To add an enterprise SSO connector, simply follow these steps:

Navigate to Logto console > Enterprise SSO.

SSO page

Click "Add enterprise connector" button and choose your SSO provider type. Choose from prebuilt connectors for Microsoft Entra ID (Azure AD), Google Workspace, and Okta, or create a custom SSO connection using the standard OpenID Connect (OIDC) or SAML protocol.
Provide a unique name (e.g., SSO sign-in for Acme Company).

Select your SSO provider

Configure the connection with your IdP in the "Connection" tab. Check the guides above for each connector types.

SSO connection

Customize the SSO experience and enterprise’s email domain in the "Experience" tab. Users sign in with the SSO-enabled email domain will be redirected to SSO authentication.

SSO experience

Save changes.

Set up OIDC application on your IdP

Step 1: Create an OIDC application on your IdP

Initiate the OIDC SSO integration by creating an application on the IdP side. You will need to provide the following configurations from the Logto server.

Callback URI: The Logto Callback URI, also known as the Redirect URI or Reply URL, is a specific endpoint or URL that the IdP uses to redirect the user's browser after successful authentication. After a user successfully authenticates with the IdP, the IdP redirects the user's browser back to this designated URI along with an authorization code. Logto will complete the authentication process based on authorization code received from this URI.

Fill in the Logto Callback URI in your IdP OIDC application settings form and continue to create the application. (Most of the OIDC IdPs provide a wide range of application types to choose from. To create a web-based SSO connector on Logto, please choose the Web Application type.)

Step 2: Configure OIDC SSO on Logto

After successfully creating an OIDC application on the IdP side, you will need to provide the IdP configurations back to Logto. Navigate to the Connection tab, and fill in the following configurations:

Client ID: A unique identifier assigned to your OIDC application by the IdP. This identifier is used by Logto to identify and authenticate the application during the OIDC flow.
Client Secret: A confidential secret shared between Logto and the IdP. This secret is used to authenticate the OIDC application and secure the communication between Logto and the IdP.
Issuer: The issuer URL, a unique identifier for the IdP, specifying the location where the OIDC identity provider can be found. It is a crucial part of the OIDC configuration as it helps Logto discover the necessary endpoints. To make the configuration process easier. Logto will automatically fetch the required OIDC endpoints and configurations. This is done by utilizing the issuer you provided and making a call to the IdP's OIDC discover endpoints. It is imperative to ensure that the issuer endpoint is valid and accurately configured to enable Logto to retrieve the required information correctly. After a successful fetch request, you should be able to see the parsed IdP configurations under the issuers section.
Scope: A space-separated list of strings defining the desired permissions or access levels requested by Logto during the OIDC authentication process. The scope parameter allows you to specify what information and access Logto is requesting from the IdP. The scope parameter is optional. Regardless of the custom scope settings, Logto will always send the openid, profile and email scopes to the IdP. This is to ensure that Logto can retrieve the user's identity information and email address properly from the IdP. You may add additional scopes to the scope parameter to request for more information from the IdP.

Step 3: Set email domains and enable the SSO connector

Provide the email domains of your organization on Logto’s connector SSO experience tab. This will enable the SSO connector as an authentication method for those users.

Users with email addresses in the specified domains will be redirected to use your SSO connector as their only authentication method.

Save your configuration

Double check you have filled out necessary values in the Logto connector configuration area. Click "Save and Done" (or "Save changes") and the OIDC enterprise SSO connector should be available now.

You don’t need to configure enterprise connectors individually, Logto simplifies SSO integration into your applications with just one click.

Navigate to: Console > Sign-in experience > Sign-up and sign-in.
Enable the "Enterprise SSO" toggle.
Save changes.

Once enabled, a "Single Sign-On" button will appear on your sign-in page. Enterprise users with SSO-enabled email domains can access your services using their enterprise identity providers (IdPs).

Auto detect SSO sign-in via email domain

To learn more about the SSO user experience, including SP-initiated SSO and IdP-initiated SSO, refer to User flows: Enterprise SSO.

Testing and Validation

Return to your Python app. You should now be able to sign in with OIDC enterprise SSO. Enjoy!

Create an application in Logto​

Integrate Flask SDK​

Installation​

Init LogtoClient​

Implement sign-in and sign-out​

Handle authentication status​

Checkpoint: Test your application​

Add OIDC enterprise SSO connector​

Set up OIDC application on your IdP​

Step 1: Create an OIDC application on your IdP​

Step 2: Configure OIDC SSO on Logto​

Step 3: Set email domains and enable the SSO connector​

Save your configuration​

Enable OIDC enterprise SSO connector in Sign-in Experience​

Testing and Validation​

Further readings​