- [NetXMS](https://www.netxms.org/) - Open Source network and infrastructure monitoring and management. ([Source Code](https://github.com/netxms/netxms)) `LGPL-3.0/GPL-3.0``Java/C++/C`
- [Observium Community Edition](http://www.observium.org/) - Network monitoring and management platform that provides real-time insight into network health and performance. `QPL-1.0``PHP`
- [OMD](http://omdistro.org/) - The Open Monitoring Distribution.
- [Performance Co-Pilot](http://pcp.io) - Lightweight, distributed system performance and analysis framework.
- [Performance Co-Pilot](http://pcp.io) - Lightweight, distributed system performance and analysis framework. ([Source Code](https://github.com/performancecopilot/pcp)) `LGPL-2.1/GPL-2.0``C`
- [PHP Server Monitor](https://www.phpservermonitor.org/) - Open source tool to monitor your servers and websites. ([Source Code](https://github.com/phpservermon/phpservermon))
- [PhpSysInfo](https://phpsysinfo.github.io/phpsysinfo/) - A customizable PHP script that displays information about your system nicely. ([Source Code](https://github.com/phpsysinfo/phpsysinfo))
- [Prometheus](https://prometheus.io/) - Service monitoring system and time series database. ([Source Code](https://github.com/prometheus/prometheus)) `Apache-2.0``Go`