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 Naver 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 Naver 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 Naver connector

To enable quick sign-in and improve user conversion, connect with .NET Core (Razor Pages) as an identity provider. The Logto social connector helps you establish this connection in minutes by allowing several parameter inputs.

To add a social connector, simply follow these steps:

1. Navigate to Console > Connectors > Social Connectors.
2. Click "Add social connector" and select "Naver".
3. Follow the README guide and complete required fields and customize settings.

note:

If you are following the in-place Connector guide, you can skip the next section.

Set up Naver login

Developer Site Only Korean Support Now

Currently Naver Developers site only supports Korean. Please consider use a translator.

For the Production

• For the production, you have to get review from Naver team. Otherwise, only registered users can sign in.
  • You can add a tester from 맴버관리(Member Manage) menu.
• To get a review, please check 애플리케이션 개발 상태(Application Devlopment Status) from API 설정(API Setting) from your application project setting.

Set up a project in the Naver Developers

• Visit the Naver Developers and sign in with your Naver account.
• Click the Application -> 어플리케이션 등록 from the menu to create new project.
• Follow the instruction below to create application.

Application Name (어플리케이션 이름)

• Type your application name on 어플리케이션 이름 (This name is shown while a user sign in.)

API Usage (사용 API)

• Choose 네이버 로그인(Naver Login) for 사용 API(API Usage)
• Check 이메일 주소(Email Address), 별명(Nickname), 프로필 사진(Profile Image) as 필수(Neccessary) from 권한(Role) (You can check 추가(Add) as optional these options, but you cannot get the information from the user.)

Sign in Open API Service Environment (로그인 오픈 API 서비스 환경)

• For 로그인 오픈 API 서비스 환경(Sign in Open API Service Environment), add two environment PC웹(PC Web) and 모바일웹(Mobile Web).

PC Web (PC 웹)

• For 서비스 URL(Service URL), type http(s)://YOUR_URL (ex. https://logto.io)
• For 네이버 로그인(Naver Login) Callback URL, type http(s)://YOUR_URL/callback/${connector_id} (e.g. https://logto.io/callback/${connector_id})

Mobile Web (Mobile 웹)

• For 서비스 URL(Service URL), type http(s)://YOUR_URL (ex. https://logto.io)
• For 네이버 로그인(Naver Login) Callback URL, type http(s)://YOUR_URL/callback/${connector_id} (e.g. https://logto.io/callback/${connector_id})

caution:

The connector_id can be found on the top bar of the Logto Admin Console connector details page.

Configure Logto

Config types

Name	Type
clientId	string
clientSecret	string

clientId

clientId is Client ID of your project. (You can find it from 애플리케이션 정보(Application Info) of your project from Naver developers.)

clientSeceret

clientSecret is Client Secret of your project. (You can find it from 애플리케이션 정보(Application Info) of your project from Naver developers.)

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 Naver connector should be available now.

Enable Naver connector in Sign-in Experience

Once you create a social connector successfully, you can enable it as a "Continue with Naver" button in Sign-in Experience.

1. Navigate to Console > Sign-in experience > Sign-up and sign-in.
2. (Optional) Choose "Not applicable" for sign-up identifier if you need social login only.
3. Add configured Naver connector to the "Social sign-in" section.

Testing and Validation

Return to your .NET Core (Razor Pages) app. You should now be able to sign in with Naver. 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.