Loading a URL on the local lan such as URL/index.php?runzmday=true

[kevintierney]

Yes, it’s fairly easy.

Here’s the official docs on how to do it
http://docs.smartthings.com/en/latest/smartapp-developers-guide/calling-web-services-in-smartapps.html

Here’s an example that does a HTTP post when a virtual switch is turned on. Changing from POST to GET should be minimal

tierneykev/SmartThings/blob/master/smartapps/tierneykev/post-tester.src/post-tester.groovy