I have just discovered uptime robot, it monitors the availability and responsiveness of my web sites. It’s simple and free and I am quite excited.
My monitors are on the web here …. and also via http://bit.ly/2H1M0DO.
It reports via the web, via email and via twitter, it’s regularity can be tuned down to a minimum threshold of 5 mins, and it captures and reports response time stats. It also has an android app.