Here's a simple one-file example:
#include <iostream>
#include <cpprest/http_listener.h>
using namespace web::http::experimental::listener;
using namespace web::http;
int main()
{
uri_builder uri(L"http://localhost:2001/");
http_listener listener(uri.to_uri());
listener.support(methods::GET, [](http_request req)
{
std::cout << "Serving GET" << std::endl;
req.reply(status_codes::OK, U("<html><body><h1>It works!</h1>(Casablanca, that is.)</body></html>"), U("text/html"));
});
listener.open().wait();
fgetc(stdin);
listener.close().wait();
return 0;
}