---
title: Introduction
description: Authenticate multiple applications using SuperTokens and OAuth2 for unified login across platforms.
sidebar:
  order: 1
---

## Overview

The **Unified Login** feature helps you in scenarios which involve different types of applications using a common **Authorization Server**.
With it you can configure a common **OAuth2 Provider** that authenticates all your clients.


## Prerequisites

<PaidFeatureCallout managedOnly />

Before you can dive deeper in the functionality there are a few things to keep in mind:
- The feature is available with the **SuperTokens Managed Service**.
It is not included in the **Self-Hosted** version.
- You can use it with the `Node.js` or the `Python` backend SDKs.
On `golang` you have to wait for the next releases or configure a separate **Authorization Service**.
- Magic link based login is not supported. However, you can switch to `email`/`SMS` **OTP** instead. This method offers the same level of security.
- *Step Up Authentication* is not available out of the box. You have to use customizations to support the flow.

## Getting started

Three separate quickstart guides are available for you to follow.
They organize the content based on the specific use case that you want to implement.

Before you explore a guide, read through the **OAuth2 Basics** page first.
It explains concepts used in each tutorial.

<CardGroup cols={3}>
  <Card title="OAuth2 Basics " href="/authentication/unified-login/oauth2-basics">
Go through a quick summary of the OAuth2 specifications to get accustomed with the language used in the quickstart guides.
</Card>
  <Card title="Applications with a common backend" href="/authentication/unified-login/quickstart-guides/multiple-frontends-with-a-single-backend">
Implement an authentication flow that involves multiple frontend applications that communicate with a common backend.
</Card>
  <Card title="Applications with separate backends" href="/authentication/unified-login/quickstart-guides/multiple-frontends-with-separate-backends">
Implement an authentication flow that involves multiple frontend applications that communicate with separate backends.
</Card>
  <Card title="Common authentication for web and mobile" href="/authentication/unified-login/quickstart-guides/reuse-website-login">
Use a common authentication service for both web and mobile applications.
</Card>
</CardGroup>


## Customization

To adjust the functionality to fit your use case you can explore different sections from the documentation.

<CardGroup cols={3}>
  <Card title="Work with scopes" href="/authentication/unified-login/work-with-scopes">
Discover the built-in scopes and see how you can override them.
</Card>
  <Card title="Verify Tokens" href="/authentication/unified-login/verify-tokens">
Learn how to validate tokens.
</Card>
  <Card title="Add custom claims in tokens" href="/authentication/unified-login/add-custom-claims-in-tokens">
Modify the token payload with custom claims.
</Card>
</CardGroup>