Guardian is Auth0's multifactor authentication (MFA) application that provides a simple, safe way for you to implement MFA. The Guardian app is used for two-factor authentication when logging into an application, which helps create a more secure login. With two-factor authentication your users will always need their mobile device in order to login.
Click the link below that most fits your role to learn more:
Guardian for Administrators - this page explains how to enable and use Push Notifications and SMS for MFA for signing in your users.
Guardian for Developers - this page explains how to enable Guardian, and details on how to configure it to meet your needs.
Guardian for Users - this page is for users logging into your application using Guardian, Google Authenticator or SMS. It also has troubleshooting tips for any issues they may encounter.