Show logged in status on Webflow site of back-end Angular application

I’ve created our marketing pages with Webflow and a software company have built a client application for us using Angular.

We would like to offer users a more seamless experience in moving between the marketing pages and the client application. Our main objective is to be able to show if the user is Logged in or not in our header of the Webflow site. However, i have no clue how to achieve this. Does anyone know how to achieve this? I can’t find something on the forum.

Could is this something that has to be done through a third party authenticator or could we also use a referrer property from the DOM in Webflow

Here is my site Read-Only: Webflow -

Here is the client application:
Here is the live hosted website:

What are you using to manage the members? There are a few ways to do this, but it would heavily depend on the answer to that question!