The illustrative setup
This illustrative checker queries only domains you own or are authorized to monitor and stores a small history of its own checks.
Constraints to set before building
Set a bounded schedule, timeout and retry policy so a failing remote service does not create overlapping work.
A small application workflow
Log the URL, timestamp, status and one concise error category. Keep credentials out of the URL and treat a failed HTTP request as an observation, not proof of a remote cause.
What the builder reviews
Keep authorization for the monitored sites, schedule, retention choice and a test of the alert path if you add one.
What this scenario is not
It does not provide OffVPS monitoring, uptime guarantees or permission to scan third-party services.