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.

Comprehensive monitoring solution with over 200 sensor types, user-friendly interface, and powerful capabilities such as traffic analysis, failover clustering, and remote probes. Offers email and SMS alerts, supports SNMP and WMI, provides high-availability features and detailed reporting.

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.

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

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.

Xitoring is an innovative monitoring platform (SaaS) for servers. We bring data from your server using our agent (Xitogent) to make sure your server is doing fine and avoid any downtime, performance issues, and increasing your customer’s satisfaction.

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.

The alerta monitoring system is a tool used to consolidate and de-duplicate alerts from multiple sources for quick ‘at-a-glance’ visualisation. With just one system you can monitor alerts from many other monitoring tools on a single screen.