This is an easy way to set up a monitoring system that calls your phone number if any of your websites go down. It uses Uptime Robot for continual monitoring and Twilio for voice calls. You can set it up to call multiple phone numbers as well.

It's almost free! You will have to pay for each voice call at the Twilio voice rate ($0.02 per call per callee in the USA).

It should be easy to set up on either App Engine or Heroku. Obviously, you should use a hosting platform that isn't also used for your sites.

It's the closest thing we've had to a "set it and forget it" service, since we don't need to touch it in order to add additional sites in Uptime Robot. This app has been dutifully watchful for us ever since we whipped it up one day, and since our automated monitoring has grown a lot more since then, we figured that it was time to release it into the wild.

You need to add in a few different environment variables, either through the app.yaml file or through heroku config:

• application - change "my_app_name" to your App Engine name
• APP_HOSTNAME - required for Heroku, tries to detect it on App Engine
• TWILIO_SID - find this in your Twilio account
• TWILIO_TOKEN - also find this in your Twilio account
• TWILIO_FROM - a Twilio purchased or validated phone number
• CALLEES - a comma separated list of phone numbers: 15551111111, 15552222222
• UPTIME_ROBOT_KEY - your Uptime Robot account's API key

The app checks Uptime Robot every 15 minutes (by default) but needs to be triggered from a specific URL. A cron.yaml file is provided for App Engine. If you use Heroku, one way to do it is to have Uptime Robot check to see if http://your_app_name.herokuapp.com/checksites is up every 15 minutes. Another way is to use the Heroku Scheduler.

We've found that 15 minutes is a decent value that keeps the app in the free tier of App Engine and would miss most transient outages that we see via other means anyways.

If you're using App Engine, you'll first have to pull down the libraries locally. Running pip install -r requirements.txt should do the trick. Since webapp2 is included with App Engine, you can delete that from requirements.txt or delete the module after it has downloaded. Then, you need to edit the values in app.yaml to reflect your app. Once that's done, you can just push it up to App Engine.

If you're using Heroku, you need to use heroku config to set each environment variable as described above. Then, you can deploy the app to Heroku and set up a cron job as described above.