And it is. It's not falling apart from the HN traffic and it has a lot of head room. Plus. It's doing 400k messages a day already easily.
Anyway. Thank you so much for your generosity. I am humbled and thankful for your support.
But if you don't find it fun spending time performance optimizing to the extreme, and can afford it, then there's nothing quite like massively over-provisioning hardware. It makes a lot of performance and reliability problems go away.
For this creator, his hobby is well into the realm of "could productize some component", even if just creating derivatives of this for some commercial purpose. I'd much rather spend time on that than the optimization part. My thought is HN has skewed more technical than entrepreneur over the years and the folks who are into the optimizations are more vocal in the thread. Could also just be the cohort of HN that was attracted to this article. "Send push notifications to your phone" sounds pretty technical. Or, the tech recession is changing mood about money and I'm not in tech.
As for the scale question: The server is already tuned for scale: https://ntfy.sh/docs/config/#tuning-for-scale
If you have any more ideas of what nobs to turn, let me know.