Nagios Core vs OP5 Monitor comparison

Nagios and ITRS are both solutions in the Network Monitoring Software category. Nagios is ranked #11 with an average rating of 8.7, while ITRS is ranked #39 with an average rating of 9.0. Nagios holds a 1.6% 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

7,235 Views
5,933 Comparison Views

80% willing to recommend

OP5 Monitor

Read 7 OP5 Monitor reviews

2,454 Views
1,865 Comparison Views

100% willing to recommend

Nagios Core

OP5 Monitor

Comparison Buyer's Guide

Download the report

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

Helped 893,221 peers since 2012

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

11th

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

42nd

Average Rating

8.6

Reviews Sentiment

4.4

Number of Reviews

Ranking in other categories

No ranking in other categories

Mindshare comparison

As of May 2026, in the Network Monitoring Software category, the mindshare of Nagios Core is 1.6%, 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	1.6%
OP5 Monitor	0.6%
Other	97.8%

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

"The good thing about Nagios Core is it covers everything."

"Nagios Core is stable."

"The notifications are definitely one of the most valuable features of Nagios Core. We know what to look for and what to expect when things are down."

"Open source and very flexible, with a large ecosystem of tools and custom monitors built up around Nagios."

"Nagios Core is very configurable. Whatever you want, you can do it."

"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."

"The most valuable feature depends on the project; it's great if you need to check to ensure a service is running 24/7, I can use the full solution for free, and it's flexible."

"Nagios doesn't get the respect it deserves; most likely due to the fact that it doesn't have a licensing cost."

More Nagios Core pros

"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."

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

"It monitors and continuously tests everything that is of importance to you and your users. It could be everything from monitoring disk space to CPU usage to memory. It could include determining if the response time in your e-commerce platform is quick enough, or whether you have too many bounces from some of the pages on your website. You want to monitor anything that could cost you money or time or resources. You can do that with this system. It's very flexible."

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

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

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

"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."

More OP5 Monitor pros

Cons

"I would like to see more training videos."

"Would benefit from aggregations if a particular server goes down."

"Nagios Core does not have a graphic display."

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

"The initial setup process could be easier."

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

"The dashboard should be improved."

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

More Nagios Core cons

"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."

"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."

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

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

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

"They need to improve the dashboard interface."

More OP5 Monitor cons

Pricing and Cost Advice

"It's free."

"Most the plugin features are free."

"It's free."

"The enterprise version has technical support. The version we are using is free."

"The Nagios Core (PNP4Nagios + Core) is free and can be setup by Netadmin within a few hours. The only additional cost is the cloud server."

"Nagios Core is a cheap solution."

"Lessening the price point would be an improvement."

"We are using the free version."

More Nagios Core pricing and cost advice

"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."

"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."

See which vendors are best for you

Use our free recommendation engine to learn which Network Monitoring Software solutions are best for your needs.

See recommendations

893,221 professionals have used our research since 2012.

Top Industries

By visitors reading reviews

Comms Service Provider

10%

Manufacturing Company

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

Comparisons

LibreNMS vs Nagios Core

Compared 7% of the time

Zabbix vs Nagios Core

Compared 5% of the time

Icinga vs Nagios Core

Compared 5% of the time

Centreon vs Nagios Core

Compared 5% of the time

More Nagios Core Competitors

Zabbix vs OP5 Monitor

Compared 10% of the time

PRTG Network Monitor vs OP5 Monitor

Compared 7% of the time

Opsview vs OP5 Monitor

Compared 6% of the time

Splunk Observability Cloud vs OP5 Monitor

Compared 4% of the time

Cisco Intersight vs OP5 Monitor

Compared 4% of the time

More OP5 Monitor Competitors

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.

DOWNLOAD NOW

893,221 professionals have used our research since 2012.

See our Nagios Core vs. OP5 Monitor report.

See our list of best Network Monitoring Software vendors and best IT Infrastructure Monitoring vendors.

We monitor all Network Monitoring Software reviews to prevent fraudulent reviews and keep review quality high. We do not post reviews by company employees or direct competitors. We validate each review for authenticity via cross-reference with LinkedIn, and personal follow-up with the reviewer when necessary.