On your motivation page you mention that you couldn't find something with the notification outputs you wanted. That surprises me as most of the well-known monitoring platforms support plugins/flexibility for that.
I wrote my own monitoring system which does a lot of monitoring stuff, for example:
* Testing SMTP hosts.
* Testing SSH hosts.
* Testing MySQL databases.
* Testing websites.
* (Much more too!)
There are a lot of options even for testing websites though; testing the status code is 200, testing that some specific text is present in the output, testing that the results match a given regular expression. Handling redirections, or not, submitting data via POST, etc, etc.
I wish you luck in your project, though I guess if it already meets your needs you don't need that. My own application is golang based too, and can be found here: