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 #40 with an average rating of 9.0. Nagios holds a 1.7% 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

6,461 Views
5,298 Comparison Views

80% willing to recommend

OP5 Monitor

Read 7 OP5 Monitor reviews

2,118 Views
1,610 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: April 2026).

Buyer's Guide

Nagios Core vs. OP5 Monitor

April 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

40th

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 April 2026, in the Network Monitoring Software category, the mindshare of Nagios Core is 1.7%, 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	1.7%
OP5 Monitor	0.6%
Other	97.7%

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.

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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.

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Quotes from Members

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

Pros

"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."

"We use the product to monitor server applications."

"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 scalability of Nagios Core is very good, we can add as many hosts as we like, and we can work with the concept master and client, making it very scalable and easy to use."

"Its an awesome product to use."

"The application performance monitoring feature is valuable, and we primarily use it for user experience monitoring and determining which layer the problem happened to resolve it."

"The most valuable features are the reports and the way it generates the report in a graphical manner."

"Nagios Core is a great solution for monitoring pretty much any size of deployment but you do need to know your way around a Linux system to set it up and run it."

More Nagios Core pros

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

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

"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."

"The API makes it pretty easy to integrate with any system."

"The best feature is that it is very relatable, stable, and scalable."

"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."

"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."

More OP5 Monitor pros

Cons

"Generally, it does what I need it to do, but better error reporting would be great."

"Nagios' great customizability is also one of its greatest drawback."

"Making it a little easier to configure and set up from the start would help. There are multiple layers that you have to wade through to be able to set it up, to do it the right way, and to get it to do what you want it to do."

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

"I believe Nagios Core will need to provide an option for big data platforms in the future."

"I would like to see more training videos."

"The initial setup was complex, mainly because it was in Linux and had many packages that we're not used to."

"t was a little hard to get our setup represented in the configuration."

More Nagios Core cons

"They need to improve the dashboard interface."

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

"We do not get performance reports properly."

"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."

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

"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."

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

More OP5 Monitor cons

Pricing and Cost Advice

"Nagios Core is free to use."

"The product is cheaply priced."

"The solution is expensive."

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

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

"It's free."

"We are using the free version."

"Lessening the price point would be an improvement."

More Nagios Core pricing and cost advice

"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..."

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

"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%

Comms Service Provider

10%

Computer Software Company

Financial Services Firm

Manufacturing Company

12%

Financial Services Firm

12%

Government

11%

Healthcare Company

10%

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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Compared 8% of the time

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Compared 6% of the time

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Compared 5% of the time

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Compared 4% of the time

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Product Reports

Buyer's Guide

Nagios Core

April 2026

Download Nagios Core product report

Buyer's Guide

OP5 Monitor

April 2026

Download OP5 Monitor product report

Overview

Nagios Core offers a versatile monitoring solution that efficiently manages notifications, reporting, and resource usage. Its open-source architecture provides flexibility and customization options for comprehensive infrastructure health management.

Nagios Core, known for its extensible plugin architecture, proactively enhances infrastructure management with customizable notifications and reliable reporting. Seamlessly integrating various plugins, it offers real-time dashboards and efficient alerting systems for thorough monitoring. Its adaptability and ease of configuration make it popular among users seeking flexible monitoring solutions. However, improvements in the web interface, scalability, performance, and visualization are needed to enhance accessibility. Users seek better alert mechanisms, more robust PDF export features, and simpler setup processes for increased efficiency.

What are the key features of Nagios Core?

Customizable Notifications: Tailor alerts to suit specific needs.
Reliable Reporting: Provides detailed insights into system performance.
Light Resource Usage: Operates efficiently with minimal resource demands.
Extensible Plugin Architecture: Supports a wide range of third-party integrations.
Real-Time Dashboards: Offers instant insights into system health.

What benefits should users expect from Nagios Core?

Flexibility: Allows detailed customization for unique monitoring requirements.
Open-Source Nature: Encourages community-driven enhancements and support.
Integration Capabilities: Facilitates seamless interaction with other tools and platforms.
Adaptability: Supports monitoring across different environments seamlessly.

In many industries, Nagios Core is integral to monitoring infrastructure and services, including cloud servers, applications, and network devices. Users rely on it for issue detection, capacity planning, and maintaining system stability in environments like AWS and on-premise servers. Its capabilities in CPU, memory, and bandwidth monitoring along with alert systems support sectors needing real-time oversight of critical equipment.

Nagios

OP5 Monitor delivers real-time IT infrastructure monitoring with extensive customization options through open-source plugins. Its intuitive interface and cost-effectiveness make it a preferred choice for efficient performance monitoring and task automation.

OP5 Monitor integrates seamlessly with systems, offering customizable dashboards and efficient performance tracking for networks, servers, applications, databases, and cloud environments. It supports LDAP and local user accounts, providing timely insights to prevent downtime. The documentation enhances integration ease, though its user interface could benefit from updates. Improved APIs, better report capabilities, and enhanced platform integration are needed. Effective in healthcare, maritime, and diverse sectors, it provides global deployments with tailored monitoring solutions.

What are the key features of OP5 Monitor?

Real-Time Monitoring: Tracks performance and alerts users immediately on anomalies.
Seamless Integration: Works effectively with existing systems and infrastructure.
Extensive Customization: Offers open-source plugins for personalized configurations.

What benefits or ROI should users consider in reviews for OP5 Monitor?

Cost-Effectiveness: Provides robust features at a competitive price.
User-Friendly Interface: Simplifies monitoring processes for administrators.
Efficiency in Performance Monitoring: Automates tasks and optimizes resource use.

In industries like healthcare, maritime, and others, OP5 Monitor automates tracking and alerts, easing manual checks to enhance quality. Its global deployments provide tailored monitoring for CPU, memory, and disk space, efficiently managing both on-premise and cloud environments for large-scale operations.

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

April 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: April 2026.

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