I would like to a deploy a program (more on which later) to the Apple Store, and I have a couple of questions regarding Apple Pay API usage. My product will be a paid program, and I have some problems with the Apple Pay API due to technical reasons.

My program is an "Electron-like" application, it consists of two parts, backend, and UI. The "Backend" runs directly in the user's computer, it's written in Python and Flask. The "UI" is actually a browser that opens a webpage from the "Backend", and interacts with it using AJAX.

The issue here is that I don't understand how in-app payments can be implemented. As far as I understand, the only option to deploy a paid application and the Apple Store is to use Apple Pay API, which is only available from Swift or Objective-C. I don't understand how can I use Apple Pay API, how I can check for a valid payment, etc. Can you please send me some kind of guide, tutorial, or instruction that can help me to use Apple Pay in my program?

Thank you very much.

P.S. If you need any other technical information, I will provide it, please.