Polling session

// check every 15 minutes if the SSO session is still active
setInterval(function() {
  // if the token is not in local storage, there is nothing to check (that is, the user is already logged out)
  if (!localStorage.getItem('userToken')) return;
  auth0.checkSession(function (err, data) {
    if (err) {
      // if we get here, it means there is no session on Auth0,
      // then remove the token and redirect to #login
      localStorage.removeItem('userToken');
      window.location.href = '#login';
    }
  });
}, 900000)

In some multi-application scenarios, where Single Logout is desired (a user logging out of one application needs to be logged out of other applications), an application can be set up to periodically poll Auth0 using checkSession() to see if a session exists. If the session does not exist, you can then log the user out of the application. The same polling method can be used to implement silent authentication for a Single Sign-on (SSO) scenario.

The poll interval between checks to checkSession() should be at least 15 minutes between calls to avoid any issues in the future with rate limiting of this call.

https://auth0.com/docs/api-auth/tutorials/silent-authentication#polling-with-checksession-
https://auth0.com/docs/libraries/auth0js/v9#using-checksession-to-acquire-new-tokens