Better Uptime vs Nagios

Better Uptime (now part of Better Stack) is a website and infrastructure monitoring service that checks uptime every 30 seconds from multiple global locations. It provides incident management, on-call scheduling, and public status pages.

Nagios is Long-established open-source infrastructure monitoring system for servers, networks, and services with an extensive plugin ecosystem.. It is available under a free model. This tool falls under the monitoring category.