How to build Tencent SMS passwordless sign-in with .NET Core (Blazor WebAssembly)

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 Tencent sign-in experience (user authentication) with .NET Core (Blazor WebAssembly) and Logto.

Prerequisites

A running Logto instance. Check out the introduction page to get started.
Basic knowledge of .NET Core (Blazor WebAssembly).
A usable Tencent 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 ".NET Core (Blazor WebAssembly)" 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 .NET Core (Blazor WebAssembly) with Logto

tip:

The following demonstration is built on .NET Core 8.0 and Blorc.OpenIdConnect.
The .NET Core sample projects are available in the GitHub repository.

Installation

Add the NuGet package to your project:

dotnet add package Blorc.OpenIdConnect

Add script references

Include Blorc.Core/injector.js the index.html file:

index.html
<head>
  <!-- ... -->
  <script src="_content/Blorc.Core/injector.js"></script>
  <!-- ... -->
</head>

Register services

Add the following code to the Program.cs file:

Program.cs
using Blorc.OpenIdConnect;
using Blorc.Services;

builder.Services.AddBlorcCore();
builder.Services.AddAuthorizationCore();
builder.Services.AddBlorcOpenIdConnect(
    options =>
    {
        builder.Configuration.Bind("IdentityServer", options);
    });

var webAssemblyHost = builder.Build();

await webAssemblyHost
    .ConfigureDocumentAsync(async documentService =>
    {
        await documentService.InjectBlorcCoreJsAsync();
        await documentService.InjectOpenIdConnectAsync();
    });

await webAssemblyHost.RunAsync();

info:

There's no need to use the Microsoft.AspNetCore.Components.WebAssembly.Authentication package. The Blorc.OpenIdConnect package will take care of the authentication process.

Configure redirect URIs

Before we dive into the details, here's a quick overview of the end-user experience. The sign-in process can be simplified as follows:

Your app invokes the sign-in method.
The user is redirected to the Logto sign-in page. For native apps, the system browser is opened.
The user signs in and is redirected back to your app (configured as the redirect URI).

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.

note:

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

Configure redirect URIs

Switch to the application details page of Logto Console. Add a redirect URI http://localhost:3000/callback.

Just like signing in, users should be redirected to Logto for signing out of the shared session. Once finished, it would be great to redirect the user back to your website. For example, add http://localhost:3000/ as the post sign-out redirect URI section.

Then click "Save" to save the changes.

Configure application

Add the following code to the appsettings.json file:

appsettings.json
{
// ...
IdentityServer: {
  Authority: 'https://<your-logto-endpoint>/oidc',
  ClientId: '<your-logto-app-id>',
  PostLogoutRedirectUri: 'http://localhost:3000/',
  RedirectUri: 'http://localhost:3000/callback',
  ResponseType: 'code',
  Scope: 'openid profile', // Add more scopes if needed
},
}

Remember to add the RedirectUri and PostLogoutRedirectUri to the list of allowed redirect URIs in the Logto application settings. They are both the URL of your WASM application.

Add `AuthorizeView` component

In the Razor pages that require authentication, add the AuthorizeView component. Let's assume it's the Home.razor page:

Pages/Home.razor
@using Microsoft.AspNetCore.Components.Authorization
@page "/"

<AuthorizeView>
    <Authorized>
        @* Signed in view *@
        <button @onclick="OnLogoutButtonClickAsync">
            Sign out
        </button>
    </Authorized>
    <NotAuthorized>
        @* Unauthenticated view *@
        <button @onclick="OnLoginButtonClickAsync">
            Sign in
        </button>
    </NotAuthorized>
</AuthorizeView>

Set up authentication

In the Home.razor.cs file (create it if it doesn't exist), add the following code:

Pages/Home.razor.cs
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Components;
using Microsoft.AspNetCore.Components.Web;
using Blorc.OpenIdConnect;
using Microsoft.AspNetCore.Components.Authorization;

[Authorize]
public partial class Home : ComponentBase
{
    [Inject]
    public required IUserManager UserManager { get; set; }

    public User<Profile>? User { get; set; }

    [CascadingParameter]
    protected Task<AuthenticationState>? AuthenticationStateTask { get; set; }

    protected override async Task OnInitializedAsync()
    {
        User = await UserManager.GetUserAsync<User<Profile>>(AuthenticationStateTask!);
    }

    private async Task OnLoginButtonClickAsync(MouseEventArgs obj)
    {
        await UserManager.SignInRedirectAsync();
    }

    private async Task OnLogoutButtonClickAsync(MouseEventArgs obj)
    {
        await UserManager.SignOutRedirectAsync();
    }
}

Once the user is authenticated, the User property will be populated with the user information.

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 Tencent connector

SMS connector is a method used to send one-time passwords (OTPs) for authentication. It enables Phone number verification to support passwordless authentication, including SMS-based registration, sign-in, two-factor authentication (2FA), and account recovery. You can easily connect Tencent as your SMS provider. With the Logto SMS connector, you can set this up in just a few minutes.

To add a SMS connector, simply follow these steps:

Navigate to Console > Connector > Email and SMS connectors.
To add a new SMS connector, click the "Set up" button and select "Tencent".
Review the README documentation for your selected provider.
Complete the configuration fields in the "Parameter Configuration" section.
Customize the SMS template using the JSON editor.
Test your configuration by sending a verification code to your Phone number.

note:

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

Set up Tencent SMS connector

Create an Tencent Cloud account

Go to the Tencent Cloud website and register your account if you don't have one.

Enable and Configure Tencent Cloud SMS

Sign-in with your account at the Tencent Cloud website and go to the SMS service console page.
Click the “Free Trial” (免费试用) button on the SMS service page and follow the setup steps.
Agree to the “Terms of SMS Service Activation” (短信开通服务条款) and click “Activate Service” (开通服务) to proceed.
On the “SMS Console Overview” (短信服务控制台概览), choose “Domestic Messages”(国内消息) or “International/Hong Kong, Macao, Taiwan Messages”(国际/港澳台消息) from the sidebar based on your needs.
Add a signature and template for SMS messages. Note:
- When adding a “Signature” (签名), select “Verification Code” (验证码) under the "Applicable Scenarios" (模版类型) field.
- When adding a template, choose “Verification Code” as the template type.
- Include a placeholder {1} in the template content, which will be replaced by a randomly generated code.
- Templates with multiple placeholders are not supported. Use or create a single-placeholder template.
Submit the signature and template for approval. After submission:
- Wait for them to take effect.
- Test SMS can be sent from the “SMS Console Overview” (短信服务控制台概览). Approved signatures and templates can be used directly for testing, or use the testing templates provided if they are still under review.
- Ensure your account has sufficient balance for testing and pre-register the test phone number to receive SMS successfully.

For detailed guidance, click the “Getting Started Guide” (新手配置指引) tab in the SMS Console Overview.

Compose the connector JSON

Go to the “SMS Console Overview” and hover over your avatar in the top-right corner. Navigate to “Access Management > Access Keys > API Keys” to generate your AccessKey ID and AccessKey Secret after completing security verification. Please keep them properly.
From the “Domestic Messages” (国内消息) or “International/Hong Kong, Macao, Taiwan Messages” (国际/港澳台消息) tab, retrieve the “Signature Name” (签名名称) and “Template Code” (模版 CODCE).
- For testing templates, check the “Getting Started” (快速开始) tab under "Test-Exclusive Templates" (测试专用签名模版).

Configure the Tencent Cloud SMS Connector with the following fields:
- accessKeyId and accessKeySecret: Use the credentials from step 1.
- signName: The signature name obtained in step 2. This applies to all templates.
- Add multiple templates for different scenarios if needed. Example for a single template:
  - templateCode: Retrieved from the “Template Code” in step 2.
  - usageType: Specify one of Register, SignIn, ForgotPassword, or Generic for different scenarios (Logto-specific property).
  - Ensure templates are configured for all four scenarios to complete the flow.
- sdkAppId: Found in “Application Management” (应用管理).
- region: Specify the supported region from the “Sending Documentation” (发送文档).

Test Tencent Cloud SMS connector

You can type in a phone number and click on "Send" to see whether the settings can work before "Save and Done".

That's it. Don't forget to Enable connector in sign-in experience.

Config types

Name	Type
accessKeyId	string
accessKeySecret	string
signName	string
region	string
sdkAppId	string
templates	Template[]

Template Properties	Type	Enum values
templateCode	string	N/A
usageType	enum string	'Register' \| 'SignIn' \| 'ForgotPassword' \| 'Generic'

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 Tencent connector should be available now.

Once you create a connector successfully, you can enable phone number-based passwordless login and registration.

Navigate to Console > Sign-in experience > Sign-up and sign-in.
Set up sign-up methods (Optional):
1. Select "Phone number" or "Email or phone number" as the sign-up identifier.
2. "Verify at sign-up" is forced to be enabled. You can also enable "Create a password" on registration.
Set up sign-in methods:
1. Select Phone number as one of sign-in identifiers. You can provide multiple available identifiers (email, phone number, and username).
2. Select "Verification code" and / or "Password" as the authentication factor.
Click "Save changes" and test it in "Live preview".

In addition to registration and login via OTPs, you can also have password recovery and -based security verification enabled, as well as linking Phone number to profile. See End-user flows for more details.

Testing and Validation

Return to your .NET Core (Blazor WebAssembly) app. You should now be able to sign in with Tencent. Enjoy!

Create an application in Logto​

Integrate .NET Core (Blazor WebAssembly) with Logto​

Installation​

Add script references​

Register services​

Configure redirect URIs​

Regarding redirect-based sign-in​

Configure redirect URIs​

Configure application​

Add AuthorizeView component​

Set up authentication​

Checkpoint: Test your application​

Add Tencent connector​

Set up Tencent SMS connector​

Create an Tencent Cloud account​

Enable and Configure Tencent Cloud SMS​

Compose the connector JSON​

Test Tencent Cloud SMS connector​

Config types​

Save your configuration​

Enable Tencent connector in Sign-in Experience​

Testing and Validation​

Further readings​

Create an application in Logto

Integrate .NET Core (Blazor WebAssembly) with Logto

Installation

Add script references

Register services

Configure redirect URIs

Regarding redirect-based sign-in

Configure redirect URIs

Configure application

Add `AuthorizeView` component

Set up authentication

Checkpoint: Test your application

Add Tencent connector

Set up Tencent SMS connector

Create an Tencent Cloud account

Enable and Configure Tencent Cloud SMS

Compose the connector JSON

Test Tencent Cloud SMS connector

Config types

Save your configuration

Enable Tencent connector in Sign-in Experience

Testing and Validation

Further readings