Which monitoring system with the ability to notify about problems to choose?

Question

Monitoring

There are several self-written sites and scripts that run in cron. They do not always work out correctly, sometimes they can change (for example, partner APIs have changed). You need a system (like Sentry) that:

• Has an API for receiving events from applications
  
• Allows you to configure notification for specific errors/events
  
• What I did not find from anyone is to configure notifications sent WHEN there are NO events for some time (for example, cron, which should run once a day. Stopped sending "I'm alive" events to the system)
  
• Setting up alerts (rules, users for notifications) should be done by an inexperienced user in settings and programming.
  

Which system will meet these requirements?

Answer 1

Zabbix.

Answer 2

nagios