Is it possible to detect Meteor login?

I want to have a static landing page which is separate from the main Meteor app for performance reasons, but is integrated into the login flow.

e.g. new users see landing page. Returning logged in users to to main app - with the same url.

There are other discussions on this and all of them basically require the app on a subdomain, which is a bad user experience.

Is it possible to write a small Meteor app which runs on the same domain and can detect if a user has logged into the main app and redirect as needed?

Some ideas:

You could check the login token from any page, without Meteor, as long as you’re on the same domain:

localStorage.Meteor.loginToken

And if you use a webserver like Nginx, you could probably do some routing with it to serve your Meteor app on example.com/meteor