Sure WiredTree has 24/7 monitoring services but just recently the entire WiredTree server went offline (this was for scheduled maintenance). At this time I didn’t receive any email alerts telling my sites were down so I’ve been looking for an additional monitoring service too.

There are a lot of services out there but most of the free services only check your sites every 30 minutes (or longer) or are restricted to just one or two sites.

Uptime Dog is completely free to register for and checks all your websites every 2 minutes from two separate locations.

If any of your sites fail you’ll be sent an email immediately.

The only thing Uptime Dog ask for in return is that you link to their website.