Netdata collects metrics per second and presents them in beautiful low-latency dashboards. It is designed to run on all of your physical and virtual servers, cloud deployments, Kubernetes clusters, and edge/IoT devices, to monitor your systems, containers, and applications.

An advanced network monitoring solution to monitor network up/downtime, traffic and usage. Features include availability, performance, and bandwidth monitoring (SNMP, WMI, packet sniffing, NetFlow), instant alerts, reporting, failover clustering.

Cabot is a free, open-source, self-hosted infrastructure monitoring platform that provides some of the best features of PagerDuty, Server Density, Pingdom and Nagios without their cost and complexity.

PHP Server Monitor is a script that checks whether your websites and servers are up and running. It comes with a web based user interface where you can manage your services and websites, and you can manage users for each server with a mobile number and email address.

Netweak is a delightful, minimalist monitoring platform that gives you insights on performance and availability for your linux servers & websites.

Observium is an autodiscovering PHP/MySQL/SNMP based network monitoring which includes support for a wide range of network hardware and operating systems including Cisco, Linux, FreeBSD, Juniper, Brocade, Foundry, HP and many more.

Enterprise-ready monitoring solution that provides unparalleled flexibility for IT to address both immediate and unforeseen operational issues, including infrastructure and IT processes.

SaaS monitoring tool for linux servers and websites. Think up-time robot but with more features. You can monitor your linux hosts, windows hosts under development.

Monitis is a Cloud monitoring and IT analytics service offering Website Monitoring, Server Monitoring, Network Monitoring, Application Monitoring, Cloud Monitoring, and Custom Monitoring.

Sematext Monitoring is a full-stack IT infrastructure monitoring software that gives you real-time visibility across your infrastructure. Whether on-premise, in the cloud, or a mix of anything in between, Sematext can monitor your whole stack.

Idera, formerly CopperEgg, is an all-in-one software-as-a-service designed and priced to ensure that organizations can effectively react to infrastructure performance issues. Idera provides four essential monitoring capabilities, giving you everything you need to identify and...

CoScale provides full-stack performance monitoring, optimized for webscale and containerized production environments. The CoScale platform continuously monitors your servers, containers, and applications, as well as the impact on user experience and key business metrics.