I worked on the Site Checker System, and it is now ready enough.

The Programm checks every site in the hackclub/dns repo. I makes a simple GET Request to it.

I watch the request and wait for it to fail, than I check what exactly went wrong.
Or if it was successful if read the response and check if it is maybe the site of a hosting provider which tells that the deployment could not be found (example). I also want to do this with other hosting providers like Orchard, the problem is Orchard does not give me enough information to be sure that it is orchard and not the deployment.

When I figured that a site has a problem (or not) I do three things:

1. I write it in the database (or delete it)
2. I create/update/delete the row in the slack list (view it in slack)
3. I write a message to the #dns-alerts channel

The messages I write to #dns-alerts contains:

1. the type of the message (new problem, updated problem or problem resolved)
2. the link to the site
3. the problem type (and I am really proud on this one, because it is colored and has the same style like the links or list items, see the screenshot, or join the channel, this is done vie the slack tag block)
4. The link to the list record unless it was resolved (because than the record does no longer exist)