A subscription platform with paying subscribers that watches a source on a schedule, detects a change, and gets the right person told.
Switch between how the work ran before, and how it runs now.
In the order it was built, and why each part exists.
A scheduled check against the source, running continuously rather than when someone remembers.
A change is confirmed before anything is sent, because a false alert costs more trust than a late one.
The right recipient is notified and the whole sequence is written down, so any alert can be explained afterwards.
A second process checks that the monitor itself is still running. A monitoring tool that dies quietly is worse than no monitoring tool.
Most projects are finished when they ship. This one is only useful while it is running, which changes every decision: retries, rate limits, health checks, and a separate process whose only job is to notice when the main one stops.
It is the only always on system here, and it carries paying subscribers.
Subscriptions and payments, the rules that decide what counts as a change worth sending, the recipients, coupons, and an activity log that answers why a given alert went out.
An owner has to be able to answer that question without reading code.
24/7
Runs without anyone watching it
2
Processes, one watching the other
Paying
Subscribers on the platform