com.afollestad.nocknock

The app will automatically knock on the door of your websites (or web servers) on a chosen interval to make sure they are up and responding successfully. If something is wrong, you get a notification telling you so. How does it check if your server is up? An HTTP GET request is made, the response code is checked. Nock Nock can also do custom validation on the response, by searching for a term, or even by executing a custom block of JavaScript.