How to link a site to an application?

Question

ASP.NET

Good afternoon.
I am writing a thesis on the topic "electronic diary on asp.net core + xamarin".
Students download an application where they can view grades, a statement for a month / 6 months / year, see the schedule.

Usage scenario:
1. Student looks at the schedule
2. End of the month. The student receives a notification in which it is written that the grades for the month have been set.

And editing and grading, etc. will be done by the teachers for whom the site was written. It is worth noting that students can use the site - see grades / schedule, etc.

It turns out that the site can be considered as a server, and the application is a client. If so, then I only need to write an interface (api) for the interaction between the application and the site?

Answer 1

No, the site (namely, the interface, the client part) and the mobile application are both clients, and the backend with the database is the server that must provide api to both types of clients.