Anyone know of a good tool to get something like push notifications when specific topics come up on HN? I've been thinking maybe I should build one, but I also feel like someone must have already done it by now.

You can check this [1] service that I prepared for myself then made it publicly available. For now it’s only sending popular stories as notification. Planning to add keyword feature.

[1] https://hnn.avci.me/

Would you consider adding regex support as well?

Don’t have any suggestions but as an alternative to notifications, I wrote a script to check the HN API for keywords such as “outage” “downtime” “breached” and show the results on a TV screen in my office.

Has been quite useful for the ops side of what I work on!

Cronjob to the Algolia Search API, send to your email.

There's been several, but they always get abandoned after a year or two.