Every app needs authentication and authorization. Logto is an Auth0 alternative designed for modern apps and SaaS products.
In this article, we will go through the steps to quickly build the Kakao sign-in experience (user authentication) with Vanilla JS and Logto.
Prerequisites
- A running Logto instance. Check out the introduction page to get started.
- Basic knowledge of Vanilla JS.
- A usable Kakao account.
Create an application in Logto
In you browser, open a new tab and enter the link of Logto Admin Console.
Once the page is loaded, in the "Get Started" section click the View all
link to open the application framework list page.
Choose your application type
In the opening modal, scroll to the "Single page app" section or filter all the available " Single page app" frameworks using the quick filter checkboxes on the left.
Click the "Vanilla JS" framework card to start creating your application.
Enter application name
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 Logto SDK
- The vanilla-js SDK is framework-agnostic, you can use it in any frontend framework by writing a wrapper to fit it.
- The sample project is available on our SDK repository.
Installation
Choose your favorite package manager or use the CDN to install the Logto Browser SDK.
- npm
- pnpm
- yarn
- CDN
npm i @logto/browser
pnpm add @logto/browser
yarn add @logto/browser
<!-- Special thanks to jsdelivr -->
<script type="module">
import LogtoClient from 'https://cdn.jsdelivr.net/npm/@logto/[email protected]/+esm';
</script>
Init LogtoClient
Import and init a LogtoClient
instance by passing config:
import LogtoClient from '@logto/browser';
const logtoClient = new LogtoClient({
endpoint: '<your-logto-endpoint>',
appId: '<your-application-id>',
});
The endpoint
and appId
can be found in the application details page in Logto Console.
Implement a sign-in and sign-out
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).
Regarding redirect-based sign-in
- 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.
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.
Handle redirect
There are still things to do after the user is redirected back to your application from Logto. Let's handle it properly.
const callbackHandler = async (logtoClient) => {
await logtoClient.handleSignInCallback(window.location.href);
if (!logtoClient.isAuthenticated) {
// Handle failed sign-in
alert('Failed to sign in');
return;
}
// Handle successful sign-in
window.location.assign('/');
};
Implement sign-in and sign-out
logtoClient
provides signIn
and signOut
methods to help you easily manage the authentication flow.
Before calling .signIn()
, make sure you have correctly configured Redirect URI
in Admin Console.
const isAuthenticated = await logtoClient.isAuthenticated();
const onClickSignIn = () => {
logtoClient.signIn('http://localhost:3000/callback');
};
const onClickSignOut = () => {
logtoClient.signOut('http://localhost:3000');
};
const button = document.createElement('button');
button.innerHTML = isAuthenticated ? 'Sign Out' : 'Sign In';
button.addEventListener('click', isAuthenticated ? onClickSignOut : onClickSignIn);
document.body.appendChild(button);
Calling .signOut()
will clear all the Logto data in memory and localStorage if they exist.
Handle authentication status
In Logto SDK, generally we can use logtoClient.isAuthenticated
to check the authentication status, if the user is signed in, the value will be true
, otherwise, the value will be false
.
In your vanilla JS app, you can use the isAuthenticated
status to programmatically show and hide the sign-in and sign-out buttons. Let's see how to do it.
const redirectUrl = 'http://localhost:3000/callback';
const baseUrl = 'http://localhost:3000';
// Conditional rendering of sign-in and sign-out buttons
const render = async (logtoClient) => {
const isAuthenticated = await logtoClient.isAuthenticated();
const container = document.querySelector('#container');
const onClickSignIn = () => logtoClient.signIn(redirectUrl);
const onClickSignOut = () => logtoClient.signOut(baseUrl);
const button = document.createElement('button');
button.innerHTML = isAuthenticated ? 'Sign Out' : 'Sign In';
button.addEventListener('click', isAuthenticated ? onClickSignOut : onClickSignIn);
container.append(button);
};
Open your Vanilla JS app to test if the integration works. When you click the "Sign In" button, the page should be redirected to a Logto sign-in page, and you should be able to create a new account by entering username and password and complete the sign-in process.
Add Kakao connector
To add a social connector, go to the "Connector" tab in the Admin Console, then click on "Social connectors". From there, click "Add social connector".
In the openning modal, select "Kakao" and click "Next".
On the next page, you will see a two-column layout with the README content on the left and configuration on the right.
Feel free to follow the README file in place or read the following section to complete the configuration process. If you follow the in-place guide, you can skip the next section.
Set up Kakao login
Set up a project in the Kakao Devlopers Console
- Visit the Kakao Developers Console and sign in with your Kakao account.
- Click the Add an application to create new project or choose exist project.
Configure Kakao Login
Activate Kakao Login
- Click the Product Settings -> Kakao Login from the menu.
- Turn on
Kakao Login Activation
- Add below URL into
Redirect URI
http(s)://YOUR_URL/callback/${connector_id}
(Theconnector_id
can be found on the top bar of the Logto Admin Console connector details page.)- (Please replace
YOUR_URL
with yourLogto
URL, and choosehttp
orhttps
on your situation.)
Privacy Setting
- Click the Product Settings -> Kakao Login -> Consent Item from the menu.
- Change state of
Nickname
,Profile image
, andEmail
to Required consent (You might not able to changeEmail
to Required consent because of your project setting.)
Security Setting (Optional)
- Click the Product Settings -> Kakao Login -> Security from the menu.
- Click the
Client secret code
to generate secret code. - Change
Activation state
to Enable. (If you enable it,secret code
is necessary.)
Configure Logto
Config types
Name | Type |
---|---|
clientId | string |
clientSecret | string? |
clientId
clientId
is REST API key
of your project.
(You can find it from summary
of your project from Kakao developers console.)
clientSeceret
clientSecret
is Secret Code
of your project.
(Please check Security Setting (Optional))
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 Kakao connector should be available now.
Enable Kakao connector in Sign-in Experience
Switch to the "Sign-in experience" tab, then click the "Sign-up and sign-in" tab.
If it's the first time you enter the tab, you will see a quick introduction about Sign-in Experience and its basic configuration.
Select "None" for the "Sign-up identifier" to provide minimum sign-up effort for Kakao sign-in, which may increase your conversion rate.
In the "Social sign-in" section, add "Add Social Connector" and choose "Kakao". Then you should be able to see a button with text "Continue with Kakao" in the preview section.
Finally, click "Save changes" on the bottom right corner.
Testing and Validation
Return to your Vanilla JS app. You should now be able to sign in with Kakao. Enjoy!
Further readings
Protect your API For native and single page apps, you'll need to call one or more API endpoints to retrieve and update data.
Learn more about identifying who's who and keeping your API secure.
User management We know you care about user management and activities, as we also do.
Learn more about how to know your users and see the figures like DAU and MAU graphically.
Localization From one regional business to a global corporate, the willingness to offer the best user experience won't change.
You can change current language phrases or add a new language without friction.
Customer IAM series Our serial blog posts about Customer (or Consumer) Identity and Access Management, from 101 to advanced topics and beyond.