In case it helps, there is Uptime Robot (http://uptimerobot.com) that offers free uptime monitoring for up to 50 monitors checked every 5 minutes.

And, have a pretty affordable Pro Plan (with 1-min checks).

Disclaimer: Uptime Robot people here :).

Uptime Robot has support for Zapier too (in private beta and requires contacting support for activation).

P.S. I'm a developer at Uptime Robot and Everyone Panic is a very handy integration, great job.

Apologies for going offtopic, but FYI, SpamAsssassin is marking your registration emails and alerts as spam.

Here's the important positive scores:

1.775 URIBL_BLACK Contains an URL listed in the URIBL blacklist 1.105 MIME_HTML_ONLY Message only has text/html MIME parts 0.635 HTML_MIME_NO_HTML_TAG HTML-only message, but there is no HTML tag

That is so crazy and inspiring to see such an interface + usability created with only HTML-CSS.

I like that it doesn't require any JS frameworks and still being lightweight.

A good reference worth bookmarking.