Nagios
Enterprise IT infrastructure monitoring platform.
Nagios is a self-hosted IT infrastructure monitoring suite designed to give organizations visibility into their servers, networks, applications, and cloud environments. It solves the problem of detecting and resolving system issues before they impact operations, with all monitoring data remaining on the customer's own hardware for environments that require data control, including air-gapped and regulated setups.
The product line includes several distinct solutions. Nagios XI provides enterprise-grade monitoring with threshold alerting, escalation, and reporting. Nagios Core is the open source monitoring engine. Nagios Log Server centralizes syslog, Windows Event Log, and application log collection, search, and alerting. Nagios Network Analyzer handles NetFlow, sFlow, J-Flow, and IPFIX traffic analysis with packet-level inspection. Nagios Fusion unifies multiple Nagios servers into a single tactical overview. These solutions integrate natively and through REST APIs, and can be deployed standalone or together.
Nagios is aimed at IT teams in government, finance, manufacturing, telecommunications, and other sectors. Nagios Core is free and open source. Commercial products are licensed by Node or Instance count, with no metering on ingest volume, retention, users, or query load. Annual Maintenance & Support plans provide software updates and case support. Free trials are available for Nagios XI, which offers Standard and Enterprise editions.
12 alternatives to Nagios
Ranked by how well each tool replaces Nagios: shared features, audience, price and popularity.
Open source infrastructure monitoring for networks, servers, cloud and applications
Covers 10 of 15 key features.
Free planOpen source74 out of 100 matchContact salesEnterprise network monitoring for complex, distributed infrastructure
Covers 8 of 15 key features.
Open source69 out of 100 match$500/moEnterprise-class open source observability and monitoring solution for networks, servers,云
Covers 5 of 15 key features.
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Covers 7 of 15 key features.
67 out of 100 matchContact salesComplete network monitoring with zero blind spots.
Covers 5 of 15 key features.
Free plan66 out of 100 match$200/moFull-Stack Monitoring and Observability for Hybrid IT
Covers 7 of 15 key features.
Free planOpen source65 out of 100 match$190/mo- 65 out of 100 match$20.83/mo
Free-to-use NGINX monitoring service (retiring January 31, 2026).
Covers 4 of 15 key features.
Free plan64 out of 100 matchFree- 63 out of 100 matchContact sales
Realtime server monitoring service with alerts, charts and dashboards
Covers 4 of 15 key features.
62 out of 100 match$5/mo- 61 out of 100 match$249/mo
Open source monitoring platform with Naemon compatibility and Prometheus integration
Covers 5 of 15 key features.
Free planOpen source61 out of 100 matchFree