[codegeek]

There are couple of existing tools already:

https://hnnotify.xyz/

https://hnreplies.com/

Is your tool doing anything different ?

[anandrmedia]

An email for every reply can be annoying. The extension I developed embeds an In-App Inbox inside HackerNews (If you've used Reddit, you know). So, everything stays inside HackerNews itself. No push notifications or emails.