Nagios Core vs OP5 Monitor comparison

Nagios and ITRS are both solutions in the Network Monitoring Software category. Nagios is ranked #10 with an average rating of 8.7, while ITRS is ranked #39 with an average rating of 9.0. Nagios holds a 1.9% mindshare in NMS, compared to ITRS’s 0.6% mindshare. Additionally, 80% of Nagios users are willing to recommend the solution, compared to 100% of ITRS users who would recommend it.

Nagios Core

Read 51 Nagios Core reviews

5,494 Views
4,505 Comparison Views

80% willing to recommend

OP5 Monitor

Read 7 OP5 Monitor reviews

1,753 Views
1,367 Comparison Views

100% willing to recommend

Nagios Core

OP5 Monitor

Comparison Buyer's Guide

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Executive SummaryUpdated on Oct 9, 2024

Nagios Core and OP5 Monitor are competing solutions in network monitoring. OP5 Monitor is favored for its comprehensive features and user-friendly setup, though Nagios Core has more favorable pricing.

Features: Nagios Core offers an extensive plugin architecture for customization, system integration capabilities, and flexibility for IT professionals. OP5 Monitor provides advanced scalability, sophisticated visualization tools, and an enhanced user-friendly setup, attracting large enterprises needing detailed analysis.

Room for Improvement: Nagios Core could improve by simplifying its setup process, enhancing user interface design, and providing more customer support options. OP5 Monitor could benefit from a more competitive pricing model, additional customization features, and improving its open-source accessibility for community-driven enhancements.

Ease of Deployment and Customer Service: Nagios Core features a manual setup process, which offers flexibility but can be time-consuming, even providing basic support through community resources only. OP5 Monitor offers a streamlined installation with comprehensive support options, reducing troubleshooting time and facilitating easier onboarding.

Pricing and ROI: Nagios Core is open-source, minimizing initial costs, though it may incur higher long-term management expenses due to customization needs. OP5 Monitor requires a higher initial investment but presents a solid ROI through its efficiency and full feature set, appealing to organizations seeking expansive monitoring with quick returns.

To learn more, read our detailed Nagios Core vs. OP5 Monitor Report (Updated: March 2026).

Buyer's Guide

Nagios Core vs. OP5 Monitor

March 2026

Download the complete report

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Review summaries and opinions

We asked business professionals to review the solutions they use. Here are some excerpts of what they said:

Categories and Ranking

Nagios Core

Ranking in Network Monitoring Software

10th

Ranking in IT Infrastructure Monitoring

10th

Average Rating

8.2

Reviews Sentiment

7.3

Number of Reviews

Ranking in other categories

No ranking in other categories

OP5 Monitor

Ranking in Network Monitoring Software

39th

Ranking in IT Infrastructure Monitoring

38th

Average Rating

8.6

Reviews Sentiment

4.4

Number of Reviews

Ranking in other categories

No ranking in other categories

Mindshare comparison

As of March 2026, in the Network Monitoring Software category, the mindshare of Nagios Core is 1.9%, down from 3.0% compared to the previous year. The mindshare of OP5 Monitor is 0.6%, down from 0.8% compared to the previous year. It is calculated based on PeerSpot user engagement data.

Network Monitoring Software Mindshare Distribution
Product	Mindshare (%)
Nagios Core	1.9%
OP5 Monitor	0.6%
Other	97.5%

Network Monitoring Software

Featured Reviews

Husham Yaqoob

Senior System Administrator at Interactive Group

Monitoring solution provides comprehensive visibility across IT infrastructure

The good thing about Nagios Core is it covers everything. Everything in the IT domain, you can monitor anything. You can even monitor printers, the ports of printers, Core workstations, and storage. You can monitor the workflow Core and the utilization of computes. If you want to grasp everything of your IT equipment on a single interface, you can use Nagios. It's the best one. It provides dashboards, and you can also configure your emails and alerts with it. If something is critical, you can configure it to notify via emails. It has a very handy dashboard, providing live alerts and visibility for everything.

Read full review

Sumanth Arshanapally

Senior Analyst at a tech vendor with 10,001+ employees

Monitoring ease and cost-saving benefits enhance operational efficiency

The monitoring in OP5 Monitor is very easy because we can directly use custom plugins. We can write custom scripts and use those scripts directly. It's very low cost, open, and the dashboards are easy to see. We can extract the reports easily, and this is very easy to compare. Real-time monitoring in OP5 Monitor provides data every one minute or every five minutes, enabling us to get live data from the last one minute or last five minutes. OP5 Monitor gave us proper server availability, so we can always check whether a server goes down or the server CPU and memory decreases. Before reaching a particular bottleneck situation, we identified and fixed the issue, which helped us from a cost-saving business perspective. It helped us avoid application downtime.

Read full review

Quotes from Members

We asked business professionals to review the solutions they use. Here are some excerpts of what they said:

Pros

"This is a fit for purpose product which means that if you have a definite list of requirements and are not willing, or unable, to spend money on big enterprise tools, then Nagios is a tool to go to."

"Nagios Core is a great tool for monitoring the infrastructure including MSM queues, and when we use the agent, we can add other things as well."

"Using Nagios, I'm managing more than 1000 services, which involves the following operating nodes: IBM AIX, Red Hat Enterprise Linux, HP-Unix, Windows enterprise-grade OS, Cisco router/switches, FortiGate and WatchGuard firewalls, APC UPS systems, and many more."

"The solution's most valuable feature is that it offers proper alerting capabilities."

"The solution is quite efficient."

"Key features include the GUI interface, its notification capabilities, and the real-time reporting."

"Other products are good but from the configuration point of view Nagios is really very lightweight. The price is really good in my opinion. Another important thing is that my Nagios engine still works with Dual core 8GB ram for the last 10 years."

"Extensibility is good as this makes it easy to write checks on your own."

More Nagios Core pros

"The monitoring in OP5 Monitor is very easy because we can directly use custom plugins; we can write custom scripts and use those scripts directly, it's very low cost, open, and the dashboards are easy to see."

"With limited hardware or a virtual machine, you can address a huge network, hundreds of thousands of elements that need to be monitored. Other commercial software is not on that level."

"OP5 Monitor is a great choice due to its being built on an open-source monitoring tool and provides ample opportunity for customization based on specific support requirements. It is also user-friendly and easy to manage with a wide range of plugins available for use. In comparison to other enterprise tools, such as Micro Focus, OP5 Monitor stands out for its features and cost-effectiveness, making it the best tool in the market. Customization is one of the key strengths of the tool and provides a lot of capabilities. Additionally, it is easy to find support and plugins for the tool through online resources."

"Especially with the API, where I can use the data with many other systems, it's great."

"Its open-source environment is accessible to everyone."

"The best feature is that it is very relatable, stable, and scalable. The logger is a part of the software, but it's not the most important point of it."

"We can also observe whatever we want, and there are no limitations."

"Instead of checking the logs each Monday, or checking that applications are running, and checking your ticketing system for angry users, you put this system in place and it monitors and continuously tests everything that is of importance to you and your users."

More OP5 Monitor pros

Cons

"The UI is a little outdated and graphics could be displayed in a better way."

"Cloud monitoring is an area for improvement because there aren't too many plugins available."

"Bandwidth monitoring is the pain point for me because Nagios Core does not monitor bandwidth effectively like Cacti does."

"Nagios SLA. I'm currently working on Nagios Digger, which has many code-level problems."

"This is the open source product, so it's a toolkit rather than a complete solution."

"Nagios Core could improve by adding a user interface. If you want the user interface you have to use Nagios XI."

"Lessening the price point would be an improvement."

"When compared to earlier versions, it looks like 4.x has lost the statusmap.cgi module."

More Nagios Core cons

"The user interface is not what we are used to these days, and should be improved."

"They need to improve the dashboard interface."

"We do not get performance reports properly, which needs improvement."

"IT environments today are in constant flux. This is driven by the newer cloud technologies such as Kubernetes and Docker, etc. The whole Nagios-based monitoring system that OP5 is created on top of, is based on a host-service model. There is a need for a strategy on what to do with more dynamic environments. There is some cool stuff going on in that direction."

"The user interface is not what we are used to these days, and should be improved."

"OP5 Monitor could include application monitoring in addition to infrastructure monitoring. If application business transactions were monitored, it would be helpful."

"OP5 lacks some visualization, a feature that makes some other products nice. Op5 is built for purpose, which is fine, but if you compare it with some new products, the visualization is not so appealing, especially for management... If you don't need fancy visualizations, OP5 is fine."

More OP5 Monitor cons

Pricing and Cost Advice

"Nagios Core is a cheap solution."

"The solution is expensive."

"Nagios Core is an open source solution, and there are no licensing fees."

"We are using the free version."

"We are using the open-source, unpaid version."

"We are using the free version of Nagios Core."

"I would rate the solution's pricing an eight out of ten."

"We have saved a lot of time, money, and effort in reducing disaster times, which is owed to Nagios quick alerting."

More Nagios Core pricing and cost advice

"OP5 has a very low price as a solution, compared to many other solutions out there."

"It was not expensive. And because it's less demanding in terms of hardware, you don't have to pay for another SQL or other database license, and you can have a huge installation on one machine..."

"The cost of the license and support are separate. If you want platinum call support, it will cost more than a regular call. I did not opt for it, as it is an additional cost."

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Top Industries

By visitors reading reviews

Manufacturing Company

10%

Computer Software Company

10%

Comms Service Provider

Government

Manufacturing Company

14%

Government

13%

Financial Services Firm

12%

Healthcare Company

Company Size

By reviewers

Large Enterprise

Midsize Enterprise

Small Business

By reviewers
Company Size	Count
Small Business	20
Midsize Enterprise	11
Large Enterprise	23

By reviewers
Company Size	Count
Small Business	2
Large Enterprise	5

Questions from the Community

What is your experience regarding pricing and costs for Nagios Core?

Nagios Core is a free and open-source product. We don't charge for the product itself, but we charge for the man-hour costs related to installation, configuration, ongoing operation, and maintenance.

See all answers

What needs improvement with Nagios Core?

The dashboard should be improved. It's very simple. I don't have a very clear or specific suggestion. You can change the skin of the dashboard, however, it's good for me.

See all answers

What is your primary use case for Nagios Core?

I was a senior system administrator. I've been using Nagios Core for more than ten years now. It can be used to monitor hosts, such as machines, and monitor services of any kind. I'm using it to mo...

See all answers

What is your experience regarding pricing and costs for OP5 Monitor?

The price for OP5 Monitor is fine, but we don't know the exact price because it was managed by us; the customer themselves bought it and gave it to us to monitor.

See all answers

What needs improvement with OP5 Monitor?

OP5 Monitor could include application monitoring in addition to infrastructure monitoring. If application business transactions were monitored, it would be helpful. For application-related issues, ...

See all answers

What is your primary use case for OP5 Monitor?

Our previous use case for OP5 Monitor was server monitoring.

See all answers

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Product Reports

Buyer's Guide

Nagios Core

March 2026

Download Nagios Core product report

Buyer's Guide

OP5 Monitor

March 2026

Download OP5 Monitor product report

Overview

This is IT infrastructure monitoring's industry-standard, open-source core. Free without professional support services.

Nagios

OP5 Monitor - The Complete Monitoring Solution

OP5 Monitor is a flexible and highly scalable monitoring solution for all sizes of environments. Use just one product to monitor your IT environment regardless of location, whether on-premise, in dynamic environments, public cloud or a hybrid of these.

Digital transformation adds extra layers and complexity to the IT estate by creating a hybrid IT environment of both static and dynamic environments, that can be difficult to monitor efficiently. ITRS OP5 Monitor gives enterprises full visibility over their entire IT estate through a single pane of glass, allowing them to consolidate monitoring tools and cut down costs.

ITRS

Sample Customers

Airbnb, Cisco, PayPal, FanDuel

Svenska Spel, Carus, VGL, Tele2, Viking Line, Clas Ohlson, Vanderlande, Försäkringskassan

Buyer's Guide

Nagios Core vs. OP5 Monitor

March 2026

Free Report: Nagios Core vs. OP5 Monitor

Find out what your peers are saying about Nagios Core vs. OP5 Monitor and other solutions. Updated: March 2026.

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