AppBeat is reliable website monitoring service that alerts you when there is a downtime or failure. It also measures performance and provides functional tests…

CoScale delivers full stack performance monitoring, optimized for large production and container environments, and powered by anomaly detection.

HappyApps is an online app uptime monitoring platform.

LibreNMS is an auto-discovering PHP/MySQL-based network monitoring system.

Munin is a networked resource monitoring tool that can help analyze resource trends.

NetCrunch is a Windows Server–based network monitoring tool that boasts high performance and impressive scalability even in a single-server deployment.

Cacti is a network graphing solution designed to harness the power of RRDTool's data storage and graphing functionality.

Datadog is a monitoring service for cloud-scale applications, bringing together data from servers, databases, tools, and services to present a unified view of…

Icinga is an open source computer system and network monitoring application.

Monitis is a web performance monitoring platform.

Nagios known as Nagios Core, is a free and open source computer-software application that monitors systems, networks and infrastructure.

Observium is a low-maintenance auto-discovering network monitoring platform supporting a wide range of device types, platforms and operating systems, etc.