Shopify storefront for Sass aplication

Shopify Apps
1

Hello,

I am researching possibilities to achieve such flow:

  1. Having landing page built via Shopify where end user can subscribe or buy digital products.

Domain example: (my-sass-name.com)

  1. Having a sign-in page to be part of sass-web-app, user would enter their email, submit the form (it would execute endpoint to my own sass web app.
    Domain example: (my-sass-name.com/login)

  2. Then, if user is subscribed or bought digital product, after they successfully logged (email, passwordless auth) in, they would be redirect to my sass web app.
    Domain example 1 (my-sass-name.com/sass) (if possible I would like to do redirect under same domain, just different path name).

Domain example 2 (app.my-sass-name.com) if example 1 wouldn’t be possible to achieve.

The main questions:

  1. Is it possible to achieve something like this by building custom app, that would be available in app-store?
  2. Would it be against shopify T&C ?

Any info would be appreciated.

UPDATE:

SO my vision would be something like this - when user becomes subscriber, or buys a digital product.
(There would be webhook that would notify sass-web app backend, so I could update user list).
Or if that’s not achievable - it would be possible to periodically fetch users to sync it with sass-web app db.