Building an App without Remix and with a custom Golang backend

Hello everyone, first time creating an embedded app and while the docs seems really nice I just cannot find all of the information I need. We offer services to our users based on their products, so our app would fetch the products, send it to our api and we’d do some magic with them and show the output/ statistics inside the embedded app.

I want to create an app to integrate into Shopify that will connect to our existing infrastructure. We have Golang services running and would like to keep using them.

My questions are the following,

  1. Do I have to use Remix? Is there anything special about it? Can I just use React+Vite without any framework and serve the static HTML+CSS+JS?
  2. Can I use a backend other than the supported SDKs? I don’t quite understand since the examples are all single process basically where webhooks are registered on /webhooks endpoint, while I need the webhooks to go to entirely different domain
  3. How can I respond to app being installed/ initial authentication? When the user downloads my app, I would like for him to have an account in my system, and I need to setup some stuff beforehand. So for that I somehow need to know when he initially creates the app and also have his ID or something on hand. (I can use access tokens without issues for the authorization part, but I still don’t know how to create the actual user for the first time). I could always ask the user to create an account with our service first, but that seems a bit redundant since its embedded in admin UI.

Any advice is appreciated! These were some of the the questions I had left after going through the docs and demos