Website Monitoring - need something open source
I have multiple idling VPS and I wish to use one for website monitoring. So far I used VisualPing service for this, but I want to use something open-source and self-hosted. Notifications need to be sent by email message (possibly using a SMTP configuration through MXRoute or something). Maybe someone has any experience with self-hosted projects in website monitoring.
I need some road-warrior script to easily install this self-hosted project for personal use. I am even willing to accept Docker, even though I don't like it.
As a side note: I know it is a blasphemy to bother an idling VPS, but I really need this, and it is sad to see an idling VPS from Virmach just doing nothing, especially when Debian 12 had just released.
Important note to get things out of the way: I do not intend to abuse websites with requests, just a monitor for pages every hour if possible.
EDIT: The website monitoring needs to include detection of changes.
If it works, don't fix it.