How can I get a notification when my node is down?

There is no pop-up notification as far as I'm aware. But the easiest way in my opinion, is if you have connected your phone to your node via "Zeus" or "Zap" app, you can always check if you have a connection to your node on the go. That's how I regularly check my connection wherever I am by just opening the app on my phone :)

This service claims to monitor your node and notify you if it is down. Real-time notifications is a paid service. Delayed notifications (1h) are free.

@Findel_LN, I've used that Lightning Watch service for a while now and it works well in my experience.  I get a message from a bot in Telegram if my node is unavailable and also when it comes back online.  Works with Tor.

Looks like this:

I accidentally joined the chat group but then joined the Bot,  This is nifty!  Thank you