How to build Tencent SMS passwordless sign-in with Capacitor JS

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 Capacitor JS and Logto.

Prerequisites

A running Logto instance. Check out the introduction page to get started.
Basic knowledge of Capacitor JS.
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 Native 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 "Native app" section or filter all the available "Native app" frameworks using the quick filter checkboxes on the left. Click the "Capacitor JS" 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 Capacitor JS with Logto

tip:

The following demonstration is built on Capacitor JS 5.0.6.

Installation

Install Logto SDK and peer dependencies via your favorite package manager:

npm
Yarn
pnpm

npm i @logto/capacitor
npm i @capacitor/browser @capacitor/app @capacitor/preferences

yarn add @logto/capacitor
yarn add @capacitor/browser @capacitor/app @capacitor/preferences

pnpm add @logto/capacitor
pnpm add @capacitor/browser @capacitor/app @capacitor/preferences

The @logto/capacitor package is the SDK for Logto. The remaining packages are its peer dependencies.

Init Logto client

Add the following code to your Capacitor project:

import LogtoClient, { type LogtoConfig } from '@logto/capacitor';

const logtoConfig: LogtoConfig = {
  endpoint: '<your-logto-endpoint>',
  appId: '<your-application-id>',
};

const logtoClient = new LogtoClient(config);

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.

Now, let's configure the redirect URI. The redirect URI is used to redirect the user back to your application after the authentication flow.

Ensure that the URI redirects to the Capacitor app, for example, com.example.app://callback. The value may vary depending on your Capacitor app configuration. For more details, see Capacitor Deep Links.

Then, add the following code to the onClick handler of the sign-in button:

const onClick = async () => {
  await logtoClient.signIn('com.example.app://callback');
  console.log(await logtoClient.isAuthenticated()); // true
  console.log(await logtoClient.getIdTokenClaims()); // { sub: '...', ... }
};

Implement sign-out

Since Capacitor leverages the Safari View Controller on iOS and Chrome Custom Tabs on Android, the authentication state can be persisted for a while. However, sometimes the user may want to sign out of the application immediately. In this case, we can use the signOut method to sign out the user:

const onClick = async () => {
  await logtoClient.signOut();
  console.log(await logtoClient.isAuthenticated()); // false
};

The signOut method has an optional parameter for the post sign-out redirect URI. If it's not provided, the user will be redirected to the Logto sign-out page.

The user needs to click "Done" to close the web view and return to the Capacitor app. If you want to automatically redirect the user back to the Capacitor app, you can provide the post sign-out redirect URI, for instance, com.example.app://callback/sign-out.

Ensure that the post sign-out redirect URI can redirect to the Capacitor app. Then add the following code to the onClick handler of the sign-out button:

const onClick = async () => {
  await logtoClient.signOut('com.example.app://callback/sign-out');
};

Checkpoint: Trigger the authentication flow

Run the Capacitor app and click the sign-in button. A browser window will open, redirecting to the Logto sign-in page.

If the user closes the browser window without completing the authentication flow, the Capacitor app will receive a LogtoClientError.

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 Capacitor JS app. You should now be able to sign in with Tencent. Enjoy!

Create an application in Logto​

Integrate Capacitor JS with Logto​

Installation​

Init Logto client​

Implement sign-in​

Regarding redirect-based sign-in​

Implement sign-out​

Checkpoint: Trigger the authentication flow​

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​