Alternatives to Nagios
The monitoring granddaddy
Nagios ranks #8 of 9 in Infrastructure monitoring, with an Alt Score of 82. It is licensed under GPL-2.0, freemium from $2,595 (Nagios XI Standard, 100-Node, one-time perpetual license) and available on Linux and Web. 10 of 10 checklist rows are verified against a public source.
IT and network administrators and sysadmins who need to monitor servers, networks, and applications for outages and performance issues, from small setups to large enterprise infrastructures.
A plugin-based monitoring engine (Nagios Core) that checks the status of hosts, services, and network components like servers, switches, routers, and applications, with 50+ official plugins and a large third-party plugin ecosystem via Nagios Exchange. It sends alerts when problems are detected. The commercial Nagios XI edition adds a web-based configuration interface, pre-built wizards, dashboards, and reporting on top of the core engine.
You install Nagios (or Nagios XI) on a monitoring server, define the hosts and services to watch, and attach plugins that perform the actual checks (e.g., ping, SSH, CPU, disk). Nagios runs these checks on a schedule, tracks state changes, and triggers configured notifications (email, SMS, etc.) when a host or service goes down or breaches a threshold.
Why people leave Nagios
Dashed reasons are sourced facts; the rest are opinions. Vendors can dispute.
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Ranked alternatives
Ordered by Alt Score. Click any score to see the breakdown.
Feature comparison
Rows come from the Infrastructure monitoring checklist (14 rows). Human-verified cells only. ? means the value has not been verified.
| Infrastructure monitoring checklist | Nagios | checkmk | Netdata | New Relic | Datadog | Grafana |
|---|---|---|---|---|---|---|
| Pricing model | ||||||
| Starts at | ||||||
| License | ||||||
| Platforms | ||||||
| Metrics collection | ||||||
| Dashboards | ||||||
| Alerting rules | ||||||
| Log aggregation | ||||||
| Tracing / APM | ||||||
| Self-hostable | ||||||
| Agent footprint | ||||||
| Integrations count | ||||||
| Free tier limits | ||||||
| High-availability setup |
Every fact and feature listed for Nagios is verified against its own pages. Each alternative is sourced on its own page.
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Pricing model Freemium verified 2026-07-10
Free License - 7 Nodes or 100 Services (whichever limit is reached first)
https://www.nagios.com/products/nagios-xi/ -
Platforms Linux, Web verified 2026-07-10
Linux-based OS (Ubuntu, CentOS, Debian, RHEL, or compatible)
https://www.nagios.org/projects/nagios-core/ -
License GPL-2.0 verified 2026-07-10
GNU GENERAL PUBLIC LICENSE Version 2, June 1991
https://github.com/NagiosEnterprises/nagioscore/blob/master/LICENSE -
Starts at $2,595 (Nagios XI Standard, 100-Node, one-time perpetual license) verified 2026-07-10
100-Node: $2,595
https://www.nagios.com/products/nagios-xi/ -
Status active verified 2026-07-10
nagios-4.5.13
https://github.com/NagiosEnterprises/nagioscore/releases -
Metrics collection Yes verified 2026-07-10
external data specific to the plugin used to perform the host or service check. Plugin-specific data can include things like percent packet loss, free disk space, processor load, number of current use
https://assets.nagios.com/downloads/nagioscore/docs/nagioscore/4/en/perfdata.html -
Dashboards Yes verified 2026-07-10
Create personalized tactical displays using a variety of built-in dashlets — graphs, status summaries, gauges, maps, and more.
https://www.nagios.com/products/nagios-xi/ -
Alerting rules Yes verified 2026-07-10
When a hard state change occurs
https://assets.nagios.com/downloads/nagioscore/docs/nagioscore/4/en/notifications.html -
Log aggregation Partial verified 2026-07-10
Centralized log management, analysis, and archiving for complete infrastructure visibility.
https://www.nagios.com/products/nagios-log-server/ -
Tracing / APM No verified 2026-07-10
Nagios XI, Nagios Log Server, Nagios Network Analyzer, Nagios Fusion, Nagios Core
https://www.nagios.com/products/ -
Self-hostable Yes verified 2026-07-10
Install on any Linux distribution
https://www.nagios.org/projects/nagios-core/ -
Agent footprint Yes verified 2026-07-10
Nagios Remote Plugin Executor (NRPE) is an agent used by Nagios XI for communicating with remote hosts.
https://support.nagios.com/kb/article/nrpe-agent-and-plugin-explained-612.html -
Integrations count Yes verified 2026-07-10
Showing 1-12 of 4406 Plugins.
https://exchange.nagios.org/directory/Plugins -
Free tier limits Yes verified 2026-07-10
No licensing costs, no hidden fees, no limitations. Completely free forever under GPL v2 license.
https://www.nagios.org/projects/nagios-core/ -
High-availability setup Partial verified 2026-07-10
The goal of High Availability is to ensure that if your primary Nagios XI instance stops or crashes, another instance will automatically and seamlessly take over the job of monitoring.
https://support.nagios.com/kb/article.php?id=199
FAQ
Yes. checkmk, Grafana and Zabbix have a free tier or are fully free. Free-tier limits in the comparison table are verified and dated.
checkmk, Netdata and Grafana — every license claim links its source.