If you’re not aware, compare https://www.hnreplies.com/

Thanks. Been a happy user for a few years!

I have a similar domain - https://hackernewsalerts.com - but it's for tracking replies to comments and posts you've made. It's on maintenance mode at the moment, couldn't gather as much interest as I'd hoped. Have open sourced it.

In case you continue to work on it, an RSS feed of comments would be interesting...

Hmm, why wouldn't you just use https://hnrss.github.io/ ?

Is there any difference to the existing one that made you built another one?

Yep, it notifies you when you get comments on your HN posts. The existing one only tracks replies to comments.