How to build Aliyun SMS passwordless sign-in with Webflow

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 Aliyun sign-in experience (user authentication) with Webflow and Logto.

Prerequisites

A running Logto instance. Check out the introduction page to get started.
Basic knowledge of Webflow.
A usable Aliyun 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 "Webflow" 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 Webflow with Logto

tip:

The sample project is available at Webflow project preview.

Init Logto Provider

note:

In the following steps, we assume your Webflow site is running on https://your-awesome-site.webflow.io.

In this step, we'll add global-level custom code to your Webflow site. Since NPM is not supported in Webflow, we'll use the jsdelivr.com CDN service to import the Logto SDK.

Open the "Site settings" page, and navigate to the "Custom code" section. Add the following code to the "Head code" section.

<script type="module">
  // Import \`@logto/browser\` SDK from the jsdelivr CDN
  import LogtoClient from 'https://esm.run/@logto/browser';

  // Assign the \`logtoClient\` instance to window object,
  // enabling global usage in other pages
  window.logtoClient = new LogtoClient({
    endpoint: '<your-logto-endpoint>', // E.g. http://localhost:3001
    appId: '<your-application-id>',
  });
</script>

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.

Let's switch to the Application details page of Logto Console. Add a Redirect URI https://your-awesome-site.webflow.io/callback and click "Save changes".

Return to your Webflow designer, drag and drop a "Sign in" button to the home page, and assign it an ID “sign-in” for later reference using getElementById().

<script type="module">
  const signInButton = document.getElementById('sign-in');
  const onClickSignIn = () => logtoClient.signIn('https://your-awesome-site.webflow.io/callback');
  signInButton.addEventListener('click', onClickSignIn);
</script>

Handle redirect

We're almost there! In the last step, we use https://your-awesome-site.webflow.io/callback as the Redirect URI, and now we need to handle it properly.

First let's create a "Callback" page in Webflow, and simply put some static text "Redirecting..." on it. Then add the following page-level custom code to "Callback" page.

<script type="module">
  (async () => {
    // Handle sign-in callback logic by calling the SDK method
    await logtoClient.handleSignInCallback(window.location.href);

    // Redirect back to the home page when the handling is done
    window.location.assign('https://your-awesome-site.webflow.io');
  })();
</script>

Implement sign-out

Calling .signOut() will clear all the Logto data in memory and localStorage if they exist.

After signing out, it'll be great to redirect your user back to your website. Let's add https://your-awesome-site.webflow.io as one of the Post Sign-out URIs in Admin Console (shows under Redirect URIs), and use the URL as the parameter when calling .signOut().

Implement a sign-out button

Return to the Webflow designer, and add a “Sign out” button on your home page. Similarly, assign an ID “sign-out” to the button, and add the following code to the page-level custom code.

const signOutButton = document.getElementById('sign-out');
const onClickSignOut = () => logtoClient.signOut('https://your-awesome-site.webflow.io');
signOutButton.addEventListener('click', onClickSignOut);

Handle authentication status

In Logto SDK, generally we can use logtoClient.isAuthenticated() method to check the authentication status, if the user is signed in, the value will be true; otherwise, it will be false.

In your Webflow site, you can also use it to programmatically show and hide the sign-in and sign-out buttons. Apply the following custom code to adjust button CSS accordingly.

const isAuthenticated = await logtoClient.isAuthenticated();

signInButton.style.display = isAuthenticated ? 'none' : 'block';
signOutButton.style.display = isAuthenticated ? 'block' : 'none';

Checkpoint: Test your Webflow site

Now, test your site:

Deploy and visit your site URL, the sign-in button should be visible.
Click the sign-in button, the SDK will initiate the sign-in process, redirecting you to the Logto sign-in page.
After signing in, you will be redirected back to your site, seeing the username and the sign-out button.
Click the sign-out button to sign-out.

Add Aliyun 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 Aliyun 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 "Aliyun".
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 Aliyun SMS connector

Set up a short message service in Aliyun SMS Console

Create an Aliyun account

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

Enable and Configure Aliyun Short Message Service

Sign-in with your Aliyun account at the Aliyun website and go to the SMS service console page.
Click the "Open for free" (免费开通) button on the top left of the SMS service page and begin the configuration process.
Read and agree to the "SMS service activation Agreement" (短信服务开通条款) and click "Subscribe to a service" (开通服务) to move on.
You are now on the SMS service console page, go to either "Mainland China" (国内消息) or "Outside Mainland China" (国际/港澳台消息) button on the sidebar per your use case.
Add signature and template following the guidelines, and provide the materials or information required for review.
- Remember to select "Verification Code Message" (验证码) as "Scenario" (适用场景) when filling out the signature application and also "Verification Code Message" (验证码) for "Type" (模板类型) when applying for a template review because we are using these signatures and templates to send verification code. Currently, we do not support sending SMS messages other than verification-code-related text messages.
- Also, use {{code}} as a placeholder where you want to place your digital verification code in template contents.
After submitting your SMS signature and template application, you need to wait for it to take effect. At this point, we can go back to the SMS service console page and send a test SMS. If your signatures and templates are ready for use, you can try them directly; if they are not taking effect yet, Aliyun also provides test templates.
- You may need to recharge a small amount of money before sending test messages.
- You may also be asked to bind a test phone number before sending test messages. For more details, go to "Quick Start" (快速学习) tab from the sidebar of the SMS service console page.

Compose the connector JSON

From the SMS service console page, hover on your avatar in the top right corner and go to "AccessKey Management" (AccessKey 管理), and click "Create AccessKey" (创建 AccessKey). You will get an "AccessKey ID" and "AccessKey Secret" pair after finishing security verification. Please keep them properly.
Go to the "Mainland China" (国内消息) or "Outside Mainland China" (国际/港澳台消息) tab you just visited, you can find "Signature" (签名名称) and "Template Code" (模板 CODE) easily.
- If you want to use the test-only signature and template, go to the "Quick Start" (快速学习) tab instead, and you will find them below "Signature & Templates (For Test Only)".
Fill out the Aliyun SMS Connector settings:
- Fill out the accessKeyId and accessKeySecret fields with access key pairs you've got from step 1.
- Fill out the signName field with "Signature" (签名名称) which is mentioned in step 2. All templates will share this signature name.
- You can add multiple SMS connector templates for different cases. Here is an example of adding a single template:
  - Fill the templateCode field, which is how you can control SMS context, with "Template Code" (模板 CODE) from step 2.
  - Fill out usageType field with either Register, SignIn, ForgotPassword or Generic for different use cases. (usageType is a Logto property to identify the proper use case.) In order to enable full user flows, templates with usageType Register, SignIn, ForgotPassword and Generic are required.

Test Aliyun 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
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 Aliyun 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 Webflow app. You should now be able to sign in with Aliyun. Enjoy!

Create an application in Logto​

Integrate Webflow with Logto​

Init Logto Provider​

Implement sign-in​

Regarding redirect-based sign-in​

Configure sign-in redirect URI​

Implement a sign-in button​

Handle redirect​

Implement sign-out​

Implement a sign-out button​

Handle authentication status​

Checkpoint: Test your Webflow site​

Add Aliyun connector​

Set up Aliyun SMS connector​

Set up a short message service in Aliyun SMS Console​

Create an Aliyun account​

Enable and Configure Aliyun Short Message Service​

Compose the connector JSON​

Test Aliyun SMS connector​

Config types​

Save your configuration​

Enable Aliyun connector in Sign-in Experience​

Testing and Validation​

Further readings​