Prometheus vs Nagios: Which Should You Choose in 2026?
Choosing between Prometheus and Nagios comes down to understanding what each tool does best. This comparison breaks down the key differences so you can make an informed decision based on your specific needs, not marketing claims.
By Toolradar Team · Last updated February 28, 2026 · Methodology
Short on time? Here's the quick answer
We've tested both tools. Here's who should pick what:
Prometheus
Monitoring and alerting toolkit
Best for you if:
- • You want the higher-rated option (8.8/10 vs 8.5/10)
- • You need something completely free
- • You need data visualization features specifically
- • Prometheus is an open-source monitoring system with a time-series database
- • It collects metrics, provides alerting, and powers Grafana dashboards
Nagios
The industry standard in open-source IT monitoring tools for servers, networks, applications, and services.
Best for you if:
- • You need monitoring features specifically
- • Open-source IT monitoring for servers, networks, applications, and services.
- • Offers both a free, community-supported core and an enterprise-grade paid version (Nagios XI).
| At a Glance |  Prometheus |  Nagios |
|---|---|---|
Price | Free | Free + Paid |
Best For | Data Visualization | Monitoring |
Rating | 88/100 | 85/100 |
| Feature | Prometheus | Nagios |
|---|---|---|
| Pricing Model | Free | Freemium |
| Editorial Score | 88 | 85 |
| Community Rating | No ratings yet | No ratings yet |
| Total Reviews | 0 | 0 |
| Community Upvotes | 0 | 0 |
| Categories | Data VisualizationMonitoring | MonitoringIncident Management |
How Prometheus and Nagios Compare
Prometheus
Monitoring and alerting toolkit
Free · 88/100 score
Nagios
The industry standard in open-source IT monitoring tools for servers, networks, applications, and services.
Free tier available · 85/100 score
Prometheus is a data visualization tool. Nagios is in monitoring.
Who Should Use What?
On a budget?
Prometheus is free. Nagios is freemium.
Go with: Prometheus
Want the highest-rated option?
Prometheus: 88/100. Nagios: 85/100.
Go with: Prometheus
Value user reviews?
Neither has user reviews yet.
Go with: Prometheus
3 Questions to Help You Decide
What's your budget?
Prometheus is free. Nagios is freemium. Go with Prometheus if free matters most.
What's your use case?
Prometheus is a data visualization tool. Nagios is in monitoring. Pick the category that matches your needs.
How important are ratings?
Prometheus scores higher: 88/100 vs 85/100.
Key Takeaways
Prometheus
- Higher score: 88/100 vs 85
- Completely free
- Our pick for this comparison
Nagios
- Better fit for monitoring
The Bottom Line
Prometheus (88/100) is our pick.
Frequently Asked Questions
Is Prometheus or Nagios better?
Prometheus scores 88/100 in our evaluation. Prometheus is free and Nagios is freemium.
What are Prometheus and Nagios used for?
Prometheus: Monitoring and alerting toolkit. Nagios: The industry standard in open-source IT monitoring tools for servers, networks, applications, and services..
What does Prometheus cost vs Nagios?
Prometheus is completely free. Nagios is freemium (free tier + paid plans). Visit their websites for detailed pricing.