How to build SAML enterprise SSO with Chrome extension

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 SAML enterprise SSO sign-in experience (user authentication) with Chrome extension and Logto.

Prerequisites

A running Logto instance. Check out the introduction page to get started.
Basic knowledge of Chrome extension.
A usable SAML 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 Single page app 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 "Single page app" section or filter all the available "Single page app" frameworks using the quick filter checkboxes on the left. Click the "Chrome extension" 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 Chrome extension with Logto

tip:

The following demonstration was tested on Chrome v123.0.6312.87 (arm64). Other versions should also work, as long as they support the chrome APIs used in the SDK.
The sample project is available on our GitHub repository.

Installation

npm
Yarn
pnpm

npm i @logto/chrome-extension

yarn add @logto/chrome-extension

pnpm add @logto/chrome-extension

The authentication flow

Assuming you put a "Sign in" button in your Chrome extension's popup, the authentication flow will look like this:

For other interactive pages in your extension, you just need to replace the Extension popup participant with the page's name. In this tutorial, we will focus on the popup page.

This authentication process follows the OpenID Connect (OIDC) protocol, and Logto enforces strict security measures to protect user sign-in.
If you have multiple apps, you can use the same identity provider (Logto). Once the user signs in to one app, Logto will automatically complete the sign-in process when the user accesses another app.

To learn more about the rationale and benefits of redirect-based sign-in, see Logto sign-in experience explained.

Update the `manifest.json`

Logto SDK requires the following permissions in the manifest.json:

manifest.json
{
  "permissions": ["identity", "storage"],
  "host_permissions": ["https://*.logto.app/*"]
}

permissions.identity: Required for the Chrome Identity API, which is used to sign in and sign out.
permissions.storage: Required for storing the user's session.
host_permissions: Required for the Logto SDK to communicate with the Logto APIs.

nota:

If you are using a custom domain on Logto Cloud, you need to update the host_permissions to match your domain.

Set up a background script (service worker)

In your Chrome extension's background script, initialize the Logto SDK:

service-worker.js
import LogtoClient from '@logto/chrome-extension';

export const logtoClient = new LogtoClient({
  endpoint: '<your-logto-endpoint>'
  appId: '<your-logto-app-id>',
});

Replace <your-logto-endpoint> and <your-logto-app-id> with the actual values. You can find these values in the application page you just created in the Logto Console.

If you don't have a background script, you can follow the official guide to create one.

info:

Why do we need a background script?

Normal extension pages like the popup or options page can't run in the background, and they have the possibility to be closed during the authentication process. A background script ensures the authentication process can be properly handled.

Then, we need to listen to the message from other extension pages and handle the authentication process:

service-worker.js
chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
  // In the below code, since we return `true` for each action, we need to call `sendResponse`
  // to notify the sender. You can also handle errors here, or use other ways to notify the sender.

  if (message.action === 'signIn') {
    const redirectUri = chrome.identity.getRedirectURL('/callback');
    logtoClient.signIn(redirectUri).finally(sendResponse);
    return true;
  }

  if (message.action === 'signOut') {
    const redirectUri = chrome.identity.getRedirectURL();
    logtoClient.signOut(redirectUri).finally(sendResponse);
    return true;
  }

  return false;
});

You may notice there are two redirect URIs used in the code above. They are both created by chrome.identity.getRedirectURL, which is a built-in Chrome API to generate a redirect URL for auth flows. The two URIs will be:

https://<extension-id>.chromiumapp.org/callback for sign-in.
https://<extension-id>.chromiumapp.org/ for sign-out.

Note that these URIs are not accessible, and they are only used for Chrome to trigger specific actions for the authentication process.

Update Logto application settings

Now we need to update the Logto application settings to allow the redirect URIs we just created.

Go to the application page in the Logto Console.
In the "Redirect URIs" section, add the URI: https://<extension-id>.chromiumapp.org/callback.
In the "Post sign-out redirect URIs" section, add the URI: https://<extension-id>.chromiumapp.org/.
In the "CORS allowed origins" section, add the URI: chrome-extension://<extension-id>. The SDK in Chrome extension will use this origin to communicate with the Logto APIs.
Click on Save changes.

Remember to replace <extension-id> with your actual extension ID. You can find the extension ID in the chrome://extensions page.

We're almost there! Let's add the sign-in and sign-out buttons and other necessary logic to the popup page.

In the popup.html file:

popup.html
<button id="sign-in">Sign in</button> <button id="sign-out">Sign out</button>

In the popup.js file (assuming popup.js is included in the popup.html):

popup.js
document.getElementById('sign-in').addEventListener('click', async () => {
  await chrome.runtime.sendMessage({ action: 'signIn' });
  // Sign-in completed (or failed), you can update the UI here.
});

document.getElementById('sign-out').addEventListener('click', async () => {
  await chrome.runtime.sendMessage({ action: 'signOut' });
  // Sign-out completed (or failed), you can update the UI here.
});

Checkpoint: Test the authentication flow

Now you can test the authentication flow in your Chrome extension:

Open the extension popup.
Click on the "Sign in" button.
You will be redirected to the Logto sign-in page.
Sign in with your Logto account.
You will be redirected back to the Chrome.

Check authentication state

Since Chrome provide unified storage APIs, rather than the sign-in and sign-out flow, all other Logto SDK methods can be used in the popup page directly.

In your popup.js, you can reuse the LogtoClient instance created in the background script, or create a new one with the same configuration:

popup.js
import LogtoClient from '@logto/chrome-extension';

const logtoClient = new LogtoClient({
  endpoint: '<your-logto-endpoint>'
  appId: '<your-logto-app-id>',
});

// Or reuse the logtoClient instance created in the background script
import { logtoClient } from './service-worker.js';

Then you can create a function to load the authentication state and user's profile:

popup.js
const loadAuthenticationState = async () => {
  const isAuthenticated = await logtoClient.isAuthenticated();
  // Update the UI based on the authentication state

  if (isAuthenticated) {
    const user = await logtoClient.getIdTokenClaims(); // { sub: '...', email: '...', ... }
    // Update the UI with the user's profile
  }
};

You can also combine the loadAuthenticationState function with the sign-in and sign-out logic:

popup.js
document.getElementById('sign-in').addEventListener('click', async () => {
  await chrome.runtime.sendMessage({ action: 'signIn' });
  await loadAuthenticationState();
});

document.getElementById('sign-out').addEventListener('click', async () => {
  await chrome.runtime.sendMessage({ action: 'signOut' });
  await loadAuthenticationState();
});

Here's an example of the popup page with the authentication state:

Other considerations

Service worker bundling: If you use a bundler like Webpack or Rollup, you need to explicitly set the target to browser or similar to avoid unnecessary bundling of Node.js modules.
Module resolution: Logto Chrome extension SDK is an ESM-only module.

See our sample project for a complete example with TypeScript, Rollup, and other configurations.

Add SAML enterprise SSO connector

To simplify access management and gain enterprise-level safeguards for your big clients, connect with Chrome extension 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.

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).

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

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.

Save changes.

Set up SAML SSO application on your IdP

Step 1: Create a SAML SSO application on your IdP {#step-1-create-a-saml-sso-application-on-your-idp}

Initiate the SAML SSO integration by creating an application on the IdP side. Obtain the following configurations from Logto, representing your Service Provider (SP):

Audience URI(SP Entity ID): It represents as a globally unique identifier for your Logto service, functioning as the EntityId for SP during authentication requests to the IdP. This identifier is pivotal for the secure exchange of SAML assertions and other authentication-related data between the IdP and Logto.
ACS URL: The Assertion Consumer Service (ACS) URL is the location where the SAML assertion is sent with a POST request. This URL is used by the IdP to send the SAML assertion to Logto. It acts as a callback URL where Logto expects to receive and consume the SAML response containing the user's identity information.

Fill in the Audience URI and ACS URL configurations in your IdP SAML application and continue to retrieve the following configurations from your IdP.

Step 2: Configure SAML SSO on Logto

To make the SAML SSO integration work, you will need to provide the IdP metadata to Logto. The IdP metadata is an XML document that contains all the information required for Logto to establish the trust with the IdP.

Navigate to the Connection tab. Logto provides three different ways to configure the IdP metadata:

Metadata URL: Provide the URL of the IdP metadata XML document. Logto will fetch the metadata from the URL and configure the SAML SSO integration automatically.
Upload Metadata: Upload the IdP metadata XML document. Logto will parse the XML document and configure the SAML SSO integration automatically.
Manual Configuration: Manually configure the IdP metadata.

IdP entity ID: The Entity ID of the IdP.
Single sign-on URL: The URL of the IdP Single Sign-On Service.
Signing certificate: The x509 certificate is used to verify the signature of the SAML response from the IdP.

With either of the above configurations, Logto will parse the IdP metadata and configure the SAML SSO integration accordingly.

Step 3: Configure user attributes mapping

The user attributes returned from IdP may vary depending on the IdP configuration. Logto provides a flexible way to map the user attributes returned from IdP to the user attributes in Logto. You can configure the user attributes mapping in the SAML SSO integration experience tab.

id: The unique identifier of the user. Logto will read the nameId claim from the SAML response as the user SSO identity id.
email: The email address of the user.
name: The name of the user.

Step4: Set email domains and enable the SSO connector

Provide the email domains of your organization in 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 the SAML 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 SAML 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

Navigate to SSO sign-in via manually click link button

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 Chrome extension app. You should now be able to sign in with SAML enterprise SSO. Enjoy!

Create an application in Logto​

Integrate Chrome extension with Logto​

Installation​

The authentication flow​

Regarding redirect-based sign-in​

Update the manifest.json​

Set up a background script (service worker)​

Update Logto application settings​

Add sign-in and sign-out buttons to the popup​

Checkpoint: Test the authentication flow​

Check authentication state​

Other considerations​

Add SAML enterprise SSO connector​

Set up SAML SSO application on your IdP​

Step 2: Configure SAML SSO on Logto​

Step 3: Configure user attributes mapping​

Step4: Set email domains and enable the SSO connector​

Save your configuration​

Enable SAML enterprise SSO connector in Sign-in Experience​

Testing and Validation​

Further readings​