Alternative open source certificates monitoring (Score 2)

I use my own Certwatch open source certificates monitoring tool.

It works with any certificates provider (not only Let's encrypt), any protocol (not only HTTPS) and several certificates issues (not just expiration).

I use it both for my personal domains and for our 5500+ company's domains. No need to use any third party service or one of the very expensive tools available on the market...

And I'm open to discuss potential additional features, if needed...