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Head-to-head · Server Monitoring

Prometheus vs Nagios Core

  • Updated Oct 2026
  • Both researched from official sources
  • 2 checks side by side
Higher score Prometheus #4 in Server Monitoring 9.1/10 Free plan Free plan✓ 0 of 3 features Visit Prometheus
Nagios Core #8 in Server Monitoring 8.7/10 Free plan Free plan✓ 1 of 3 features Visit Nagios Core

Prometheus leads on 0 checks, Nagios Core on 0, and 2 are even. Who comes out ahead on the 2 yes/no, price and count checks where we have data for both products. The editor score weighs everything else too.

Our verdict

  • Highest scorePrometheus · 9.1/10
  • Free planboth
  • Most featuresNagios Core · 1 of 3

Prometheus scores higher on our rubric for server monitoring: 9.1 against 8.7 out of 10; our editors rank them #4 and #8.

Prometheus is the better fit for teams building metric-based monitoring stacks. Nagios Core is the better fit for free extensible monitoring with a large ecosystem.

  • Prometheus fits best

    Teams building metric-based monitoring stacks

  • Nagios Core fits best

    Free extensible monitoring with a large ecosystem

Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.

Side by side

Feature Prometheus 9.1/10 Visit ↗ Nagios Core 8.7/10 Visit ↗
At a glance
Editor score 9.1 8.7
Ranking #4 in Server Monitoring #8 in Server Monitoring
Best for Teams building metric-based monitoring stacks Free extensible monitoring with a large ecosystem
Pricing model Free Free
Starting price Free plan Free plan
Free plan ✓ ✓
Free trial — —
Deployment Self-hosted Self-hosted
Platforms Web, Windows, macOS, Linux Linux
Support Community, Docs Community, Docs
Integrations 8 integrations 6 integrations
Built for Small business, Mid-market, Enterprise Small business, Mid-market, Enterprise
Features Prometheus 0/3 · Nagios Core 1/3
Server auto-discovery Not checked yet Not checked yet
Process monitoring Not checked yet ✓ (best)
Container monitoring Not checked yet Not checked yet
Specs
Included hosts Not checked yet Not checked yet
Metric retention Not checked yet Not checked yet
Monitoring method Not checked yet Hybrid
Supported operating systems Not checked yet Linux, Unix, Windows
Our review
Pros
  • Labeled time-series model with powerful PromQL querying
  • HTTP scraping with static and service-discovery configuration
  • Rules, federation, and integrations for extensible monitoring stacks
  • Free, GPL-licensed, self-hosted monitoring engine
  • Plugin architecture supports custom checks and metrics
  • Integrates with Grafana, Prometheus, Slack, and ServiceNow
Cons
  • Local storage is single-node
  • Broader workflows require surrounding components
  • Uses PromQL rather than SQL for querying
  • Configuration relies mainly on text files and command-line workflows
  • The platform listing is limited to Linux
  • It lacks a server auto-discovery feature
Our verdict

Prometheus is an open-source monitoring and alerting toolkit for infrastructure, applications, and services. It collects numeric metrics as labeled, timestamped time-series data, making it a strong fit for teams building metric-based…

Read the review →

Nagios Core is a free, GPL-licensed, self-hosted monitoring engine for IT infrastructure. It monitors servers, workstations, network devices, websites, applications, services, and custom metrics through a plugin-based architecture. Its…

Read the review →
  1. PrometheusServer Monitoring 9.1Free plan
  2. Nagios CoreServer Monitoring 8.7Free plan

Strengths and trade-offs

  • Prometheus — where it wins

    • Labeled time-series model with powerful PromQL querying
    • HTTP scraping with static and service-discovery configuration
    • Rules, federation, and integrations for extensible monitoring stacks

    Where it doesn't

    • Local storage is single-node
    • Broader workflows require surrounding components
    • Uses PromQL rather than SQL for querying

  • Nagios Core — where it wins

    • Free, GPL-licensed, self-hosted monitoring engine
    • Plugin architecture supports custom checks and metrics
    • Integrates with Grafana, Prometheus, Slack, and ServiceNow

    Where it doesn't

    • Configuration relies mainly on text files and command-line workflows
    • The platform listing is limited to Linux
    • It lacks a server auto-discovery feature

More comparisons

All server monitoring comparisons → · Full ranking →

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Last updated · How we research and update