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 Twilio 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 Twilio 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:

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 "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.
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 Webflow with Logto

tip:

The sample project is available at Webflow project preview.

Init Logto Provider

nota:

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>

Implement sign-in

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:

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

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 sign-in redirect URI

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".

Implement a sign-in button

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:

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

Add Twilio 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 Twilio 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:

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

nota:

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

Set up Twilio SMS connector

Register Twilio account

Create a new account on Twilio. (Jump to the next step if you already have one.)

Set up senders' phone numbers

Go to the Twilio console page and sign in with your Twilio account.

Purchase a phone number under "Phone Numbers" -> "Manage" -> "Buy a number".

tip:

Sometimes you may encounter the situation that SMS service is not supported in specific countries or areas. Pick a number from other regions to bypass.

Once we have a valid number claimed, nav to the "Messaging" -> "Services". Create a new Message Service by clicking on the button.

Give a friendly service name and choose Notify my users as our service purpose. Following the next step, choose Phone Number as Sender Type, and add the phone number we just claimed to this service as a sender.

nota:

Each phone number can only be linked with one messaging service.

Get account credentials

We will need the API credentials to make the connector work. Let's begin from the Twilio console page.

Click on the "Account" menu in the top-right corner, then go to the "API keys & tokens" page to get your Account SID and Auth token.

Back to "Messaging" -> "Services" settings page starting from the sidebar, and find the Sid of your service.

Compose the connector JSON

Fill out the accountSID, authToken and fromMessagingServiceSID fields with Account SID, Auth token and Sid of the corresponding messaging service.

You can add multiple SMS connector templates for different cases. Here is an example of adding a single template:

• Fill out the content field with arbitrary string-typed contents. Do not forget to leave {{code}} placeholder for random verification code.
• Fill out the usageType field with either Register, SignIn, ForgotPassword, Generic for different use cases. In order to enable full user flows, templates with usageType Register, SignIn, ForgotPassword and Generic are required.

Test Twilio SMS connector

You can enter 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
accountSID	string
authToken	string
fromMessagingServiceSID	string
templates	Templates[]

Template Properties	Type	Enum values
content	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 Twilio connector should be available now.

Enable Twilio connector in Sign-in Experience

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

1. Navigate to Console > Sign-in experience > Sign-up and sign-in.
2. 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.
3. 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.
4. 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 Twilio. 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.