It was a lot of fun developing UptimeButler and we learned a lot. For the actual web app we decided to give Meteor a try. The hardest part there was, that some packages contain a lot of "magic" :) But in the end, we had a pretty good feeling what we could use out of the box and what had to be done by hand.

For the workers which perform the availability checks, we use C# applications running on Linux with Mono. Fortunately we got into the BizSpark program from Microsoft, which allows us to launch our public beta with very little private equity.

We created this small uptime monitoring service. Any feedback is appreciated!