The killer feature I need is heartbeat so I can make some device send a request every 5 min and if it’s not sent then it is down. Currently using UptimeRobot for this.
Hey mate, I'm using https://healthchecks.io/ for heartbeat monitoring my crons. It's been working flawlessly for quite some time now. The UI is super clean and easy to navigate. It's also free up to 20 monitored jobs. Note - I'm not in any way related to that project.