Be sure to check out exchange.nagios.org for apache, certificate, php, Linux, and mail checks. check_http from the nagios-plugins suite should help plenty. https://support.nagios.com/kb/article.php?id=569 Compiling is pretty simple, but your OS may also have them packaged. The packages often lag the latest versions, and the packages may put the plugins in a directory unfamiliar to Nagios support techs. If you are concerned about monitoring visual elements, you may want to look at Selenium. Until this is complete, the API can be used for monitoring: https://www.perforce.com/perforce/doc.current/manuals/swarm/Content/Swarm/swarm-apidoc.html