Server Density!

An uncompromising mature enterprise-level platform designed for real-time monitoring of millions of metrics collected from tens of thousands of servers, virtual machines and network devices, effortlessly scaling to even larger environments.

Join millions of IT professionals and download Spiceworks, a free network monitoring software with network management tools, help desk ticketing app, network mapper and more.

Datadog is a monitoring service for IT, Dev & Ops teams who write and run applications at scale, and want to turn the massive amounts of data produced by their apps, tools and services into a unified view of IT infrastructure. Datadog's capabilities are provided on a SaaS-based data analytics platform that enables multiple teams to work collaboratively on infrastructure issues.

Icinga is a fork of Nagios and is backward compatible. So, Nagios configurations, plugins and addons can all be used with Icinga. Though Icinga retains all the existing features of its predecessor, it builds on them to add many long awaited patches and features requested by the user community. Icinga is an enterprise grade open source monitoring system which keeps watch over a network and any conceivable network resource, notifies the user of errors and recoveries, and generates performance data for reporting. Scalable and extensible, Icinga can monitor complex, large environments across dispersed locations. Icinga is licensed under GPL V2. »

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.

Check_MK is comprehensive IT monitoring solution in the tradition of Nagios. Check_MK is available as Raw Edition, which is 100% pure open source, and as Enterprise Edition with a lot of additional features and professional support.

OpsDash is a server monitoring, service monitoring, database monitoring, app metric monitoring and uptime monitoring solution for monitoring MySQL, PostgreSQL, MongoDB, Docker, Memcache, Redis, Apache, Nginx, Elasticsearch and more. It provides intelligent, customizable dashboards and rule-based alerting and notification via email, HipChat, Slack, OpsGenie, PagerDuty VictorOps, and Webhooks. Send in your custom metrics with StatsD and Graphite interfaces built into each agent.

Opsview Atom is ideal for personal use, SoHo setups, test or lab environments or just to get your hands dirty with all of Opsview's monitoring functionality!

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

Opsview is award winning unified service monitoring software for complex, distributed IT infrastructures.

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. CoScale simplifies monitoring and troubleshooting with automated anomaly detection and contextual insights, so you can act proactively on performance changes that impact your bottom line.

Zenoss (Zenoss Core) is an open source application, server and network management platform based on the Zope application server. Released under the GNU General Public License (GPL) version 2, Zenoss Core provides a web interface that allows system administrators to monitor availability, inventory/configuration, performance and events.