How to use Unity as REST API? [closed]

I have a question. I want to use unity project as library on website. Because I need to be able to access and dynamically change a url parameter in the project through other web applications. Unity application should also work according to this link. I think I should use the Rest API but is there a different way to do it? How can I do it if there is no other way? Can I use Unity project as REST API?