Problem Statement:
I want to implement SSO for multiple applications so that users logging into one application automatically log into the other applications.
Solution:
If the applications use the same database connection and that is the only database connection enabled in each application, then this should be seamless. Users only need to log in once.
This article has the configuration details.
If you configure your Auth0 tenant to use a custom domain and your applications share the same parent domain, you can perform silent authentication by using an invisible iframe to avoid users seeing the redirects. This requires a custom domain as modern browsers will block 3rd party cookies by default in an iframe. This article has the details.
To configure and update the session lifetime, please read here.