Here is an example of such a simplistic standalone app: Re: Networking Perl — and some commentary/discussion: Need Help in Understanding Some Code - Map and Scalar Questions.

When you run something like that with an engine like Starman (or Twiggy or plackup or…) you get a hot-restartable, hot-worker-assignable, little speed-demon with a tiny footprint that can be tested easily. Apache is deep and venerable but there are many ways to skin the HTTP cat. Many app developers today deploy on nginx or lighttpd instead for example. They do not have the feature bag apache does but they outperform it handily on several levels in simple webservice.