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 Google Workspace enterprise SSO sign-in experience (user authentication) with .NET Core (Razor Pages) and Logto.

Prerequisites

• A running Logto instance. Check out the introduction page to get started.
• Basic knowledge of .NET Core (Razor Pages).
• A usable Google Workspace 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:

1. 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.
2. 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 ".NET Core (Razor Pages)" framework card to start creating your application.
3. 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 .NET Core (Razor Pages) SDK

tip:

• The following demonstration is built on .NET Core 8.0. The SDK is compatible with .NET 6.0 or higher.
• The .NET Core sample projects are available in the GitHub repository.

Installation

Add the NuGet package to your project:

dotnet add package Logto.AspNetCore.Authentication

Add Logto authentication

Open Startup.cs (or Program.cs) and add the following code to register Logto authentication services:

Program.cs

using Logto.AspNetCore.Authentication;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddLogtoAuthentication(options =>
{
  options.Endpoint = builder.Configuration["Logto:Endpoint"]!;
  options.AppId = builder.Configuration["Logto:AppId"]!;
  options.AppSecret = builder.Configuration["Logto:AppSecret"];
});

The AddLogtoAuthentication method will do the following things:

• Set the default authentication scheme to LogtoDefaults.CookieScheme.
• Set the default challenge scheme to LogtoDefaults.AuthenticationScheme.
• Set the default sign-out scheme to LogtoDefaults.AuthenticationScheme.
• Add cookie and OpenID Connect authentication handlers to the authentication scheme.

Sign-in and sign-out flows

Before we proceed, there are two confusing terms in the .NET Core authentication middleware that we need to clarify:

1. CallbackPath: The URI that Logto will redirect the user back to after the user has signed in (the "redirect URI" in Logto)
2. RedirectUri: The URI that will be redirected to after necessary actions have been taken in the Logto authentication middleware.

The sign-in process can be illustrated as follows:

Similarly, .NET Core also has SignedOutCallbackPath and RedirectUri for the sign-out flow.

For the sack of clarity, we'll refer them as follows:

Term we use	.NET Core term
Logto redirect URI	CallbackPath
Logto post sign-out redirect URI	SignedOutCallbackPath
Application redirect URI	RedirectUri

Regarding redirect-based sign-in

1. This authentication process follows the OpenID Connect (OIDC) protocol, and Logto enforces strict security measures to protect user sign-in.
2. 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.

Configure redirect URIs

note:

In the following code snippets, we assume your app is running on http://localhost:3000/.

First, let's configure the Logto redirect URI. Add the following URI to the "Redirect URIs" list in the Logto application details page:

http://localhost:3000/Callback

To configure the Logto post sign-out redirect URI, add the following URI to the "Post sign-out redirect URIs" list in the Logto application details page:

http://localhost:3000/SignedOutCallback

Change the default paths

The Logto redirect URI has a default path of /Callback, and the Logto post sign-out redirect URI has a default path of /SignedOutCallback.

You can leave them as are if there's no special requirement. If you want to change it, you can set the CallbackPath and SignedOutCallbackPath property for LogtoOptions:

Program.cs

builder.Services.AddLogtoAuthentication(options =>
{
  // Other configurations...
  options.CallbackPath = "/Foo";
  options.SignedOutCallbackPath = "/Bar";
});

Remember to update the value in the Logto application details page accordingly.

Implement sign-in/sign-out buttons

First, add the handler methods to your PageModel, for example:

Pages/Index.cshtml.cs

public class IndexModel : PageModel
{
  public async Task OnPostSignInAsync()
  {
    await HttpContext.ChallengeAsync(new AuthenticationProperties
    {
      RedirectUri = "/"
    });
  }

  public async Task OnPostSignOutAsync()
  {
    await HttpContext.SignOutAsync(new AuthenticationProperties
    {
      RedirectUri = "/"
    });
  }
}

Then, add the buttons to your Razor page:

Pages/Index.cshtml

<p>Is authenticated: @User.Identity?.IsAuthenticated</p>
<form method="post">
  @if (User.Identity?.IsAuthenticated == true) {
    <button type="submit" asp-page-handler="SignOut">Sign out</button>
  } else {
    <button type="submit" asp-page-handler="SignIn">Sign in</button>
  }
</form>

It will show the "Sign in" button if the user is not authenticated, and show the "Sign out" button if the user is authenticated.

Checkpoint: Test your application

Now, you can test your application:

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

Add Google Workspace enterprise SSO connector

To simplify access management and gain enterprise-level safeguards for your big clients, connect with .NET Core (Razor Pages) 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:

1. Navigate to Logto console > Enterprise SSO.

2. 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.
3. Provide a unique name (e.g., SSO sign-in for Acme Company).

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

5. 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.

6. Save changes.

Set up Google Cloud Platform

Step 1: Create a new project on Google Cloud Platform

Before you can use Google Workspace as an authentication provider, you must set up a project in the Google API Console to obtain OAuth 2.0 credentials, If you already have a project, you can skip this step. Otherwise, create a new project under your Google organization.

Step 2: Config the consent screen for your application

In order to create a new OIDC credential, you need to configure the consent screen for your application.

1. Navigate to the OAuth consent screen page and select the Internal user type. This will make the OAuth application only available to users within your organization.

2. Fill in the Consent Screen settings following the instructions on the page. You need to provide the following minimum information:

• Application name: The name of your application. It will be displayed on the consent screen.
• Support email: The support email of your application. It will be displayed on the consent screen.

3. Set the Scopes for your application. In order to retrieve the user's identity information and email address properly from the IdP, Logto SSO connectors need to grant the following scopes from the IdP:

• openid: This scope is required for OIDC authentication. It is used to retrieve the ID token and get access to the userInfo endpoint of the IdP.
• profile: This scope is required for accessing the user's basic profile information.
• email: This scope is required for accessing the user's email address.

Click the Save button to save the consent screen settings.

Step 3: Create a new OAuth credential

Navigate to the Credentials page and click the Create Credentials button. Select the OAuth client ID option from the dropdown menu to create a new OAuth credential for your application.

Continue setting up the OAuth credential by filling up the following information:

1. Select the Web application as the application type.
2. Fill in the Name of your client application, Logto SSO Connector for example. This will help you to identify the credentials in the future.
3. Fill in the Authorized redirect URIs with the Logto callback URI. This is the URI that Google will 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 the authorization code received from this URI.
4. Fill in the Authorized JavaScript origins with the Logto callback URI's origin. This ensures only your Logto application can send requests to the Google OAuth server.
5. Click the Create button to create the OAuth credential.

Step 4: Set up Logto connector with the client credentials

After successfully creating the OAuth credential, you will receive a prompt modal with the client ID and client secret.

Copy the Client ID and Client secret and fill in the corresponding fields on Logto’s SSO connector Connection tab.

Now you have successfully configured a Google Workspace SSO connector on Logto.

Step 5: Additional Scopes (Optional)

Use the Scope field to add additional scopes to your OAuth request. This will allow you to request more information from the Google OAuth server. Please refer to the Google OAuth Scopes documentation for more information.

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.

Step 6: 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.

For more information about the Google Workspace SSO connector, please check Google OpenID Connector.

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 Google Workspace enterprise SSO connector should be available now.

Enable Google Workspace enterprise SSO connector in Sign-in Experience

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

1. Navigate to: Console > Sign-in experience > Sign-up and sign-in.
2. Enable the "Enterprise SSO" toggle.
3. 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).

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 .NET Core (Razor Pages) app. You should now be able to sign in with Google Workspace enterprise SSO. Enjoy!

Further readings

End-user flows: Logto provides a out-of-the-box authentication flows including MFA and enterprise SSO, along with powerful APIs for flexible implementation of account settings, security verification, and multi-tenant experience.

Authorization: Authorization defines the actions a user can do or resources they can access after being authenticated. Explore how to protect your API for native and single-page applications and implement Role-based Access Control (RBAC).

Organizations: Particularly effective in multi-tenant SaaS and B2B apps, the organization feature enable tenant creation, member management, organization-level RBAC, and just-in-time-provisioning.

Customer IAM series Our serial blog posts about Customer (or Consumer) Identity and Access Management, from 101 to advanced topics and beyond.