What to choose for writing an API server?

Question

API

It is necessary to write an API that will link the work of desktop applications (windows / linux) and a personal account on the site. Applications should download the list of questions / answers for testing students and accordingly send statistics on the results of testing to the server. Through a personal account, you need to be able to pull all the summary statistics: whether it be for a specific student or a group of students.
What language to choose for writing the server part for such a bundle: so that it can optimally hold the load and not be particularly demanding on resources?

Answer 1

Java + Spark + Jetty Embedded/ Undertow

Answer 2

You have no requirements, any server language will do (in the comments, everyone will write their favorite programming language for you).
It's not entirely clear what you mean by "loaded".
at least write up to how many simultaneous sessions?
PS if desktops transmit only statistics, then there is most likely no load. I’ll immediately note that smart students can easily hack this option if they analyze the traffic with programs like wireshark and so on. do not forget to add at least a signature, it will be more difficult, you will have to decompile in order to understand the algorithm. It is most correct, of course, to send only answers to the server, and already on the server to decide whether it is correct or not. But if your tests are not very serious, and their cheating is not particularly interesting, then of course it’s possible.