12 Best Open Source Monitor Tools in 2023 [TOP RANKINGS]

If you are concerned about analyzing the traffic on the server of the user’s request, choose the best Open Source Monitor Tool reviewed and compared here:

When a big business or application is made online, millions of users share their requests per second, and it becomes challenging to manage and track user requests. However, various applications do this task efficiently for you as they keep track of the requests and ensure that the connection is secure and stable.

So, in this article, we will discuss various open-source server monitor applications that make your work easier and more efficient.

Let us begin!

What are Open Source Monitors

Best Open Source Monitors

Monitor applications are special applications that analyze the traffic on the server and then develop the reports on the same. Such applications make it easier to comprehend data. Also, these open-source monitors can run through the entire server and check each line of code and data to find bugs and provide suggestions to fix the same.

These open-source server monitoring are equipped with features that monitor the data shared on the server and then keep track of logs to enhance security. With these applications, users can check for crashes and send responses to service requests.

Market Trends: There has been consistent growth in the open-source monitors market, which has opened doors for competition and has thrived developers to develop even more efficiently. The network monitoring market is predicted to grow up to $50 billion in 2027 from $27.6 billion in 2020, as displayed in the graph below.

network monitoring market

Expert Advice: Various factors will enhance your choice of network open-source monitors and these include auto-discovery, data mapping, event logging, alert systems, reporting, and server request management.

Frequently Asked Questions

Q #1) What is the best free network monitoring tool?

Answer: Prometheus is the best server monitoring open-source tool that provides users with amazing features.

Q #2) Is NetXMS free?

Answer: NetXMS is a free and open-source monitor tool that makes it easier for users to manage networks efficiently.

Q #3) Is OpenNMS free?

Answer: OpenNMS has a free trial version but is not a free tool.

Q #4) Is SNMP Open Source?

Answer: Not all SNMP tools are open source, but there are various tools you can alter as per users’ requirements.

Q #5) How can I monitor network traffic on open-source?

Answer: First, you must go through all the network monitoring tools and select the one you wish to use. After that, you can open the dashboard and connect it to the servers to start monitoring the traffic.

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List of the Top Open Source Monitors

Top-rated open-source server monitor list:

  1. Prometheus
  2. Zabbix
  3. Nagios
  4. Observium
  5. Checkmk
  6. EventSentry
  7. Riemann
  8. Sensu
  9. Icinga
  10. OpenNMS
  11. Cacti
  12. LibreNMS

Comparison Table of Best Open-Source Server Monitor

NameBest ForPricingSpecial featureRating
PrometheusManage data extraction from serverFreeAlerts and data managementStar_rating_5_of_5
ZabbixAdvanced SecurityFree Trial
Advanced $18,700/year
Professional $27,000/year
Expert $43,900/year
Power detectionStar_rating_4.5_of_5
NagiosMultiple OS monitoringFree trial
Number of nodes
Starts at $1,995
Starts at $3,995
Phone Support
Starts at $1995
Expendable ArchitectureStar_rating_4.5_of_5
ObserviumTraffic monitoring and managementFree
Professional $280/year
Enterprise $1400/year
Traffic monitoring and managementStar_rating_4_of_5
CheckmkPowerful automation toolStandard $904/year (including tax)
Standard Group $1773.10/year (including tax)
Managed Services $1773.10/year(including tax)
Powerful automation toolStar_rating_4_of_5

Detailed reviews:

#1) Prometheus

Best for an application that alerts you and manages all your data extracted from the server.


Prometheus is an open-source tool that focuses on simplifying server management. This tool supports multiple languages, making it easier for users to code and work in various languages. This tool focuses on customer enhancement, and for the same, it provides users with custom libraries that contain the codes of multiple processes and make the deployment easier.

This tool also contains various client libraries to manage and work with a series of features that simplify client operations. It provides data bridging features to facilitate third-party data management.


  • Highly efficient and advanced data dimensional model for users to understand the architecture.
  • A series of key-value pairs are available to identify and manage metric names for a website.
  • Users extract and manage data from the website using PromQL, which analyzes your data.
  • Generate graphs and charts from data to create comparisons and tabular data.
  • An inbuilt browser known as Grafana provides users with a secure network for managing information.
  • This tool provides integration with Grafana and a console template that enhances users’ work efficiency.
  • Store your time series to keep track of your working hours on the device.
  • Functional sharing to scale the tool with better output.
  • Highly reliable and provides local storage to track data.
  • Uses static allocation for binaries to deploy the server.
  • Provides notifications regarding the updates on the server for monitoring the server.
  • Manages database updates and dimensional information.


  • Open-source monitor.
  • Multiple integrations.


  • Complex to use for beginners.

Verdict: This is an open-source tool and has many features that make it easier for users to manage their server and alert to all the updates regarding the data extracted. It uses static allocation to deploy binaries.

Pricing: Free

Website: Prometheus

#2) Zabbix

Best for advanced security and deployment on the server end.


Zabbix is a tool to manage server information efficiently and then generate analytics reports securely. It is equipped with enhanced features like multiple integrations to automate a series of tasks that can save a lot of time for users. This tool has a better deployment technique, which ensures that code is deployed on the server and there are no possible chances of a crash.

It provides the most secure network to share information directly with the server without worrying about a data breach. The features provided by the tool enhance its scalability and thus improve the overall output gained by users.


  • It provides a transparent view of the network and architecture, making it easier for users to find and fix anomalies in the network.
  • Extract server information and process that information to develop reports to make the server more efficient.
  • Separate dashboard easily monitors the server operations.
  • A different cloud monitoring feature lets users measure cloud server traffic.
  • Manage metrics and record all the data collected from the server.
  • The robust detection of this tool supports users to detect issues with the server and provides support tips to fix the issues quickly.
  • Advanced alerting feature manages your notifications.
  • Charts and report features visualize data and share it in a presentable manner.
  • Pane of glass feature makes working easier.
  • An advanced business monitory feature focused on generating metrics and reports.


  • Power detection.
  • Metric meter.


  • It does not provide architectural insights.

Verdict: This is a powerful tool that uses an advanced search algorithm that goes through web pages and looks for fixes to help the users fix the website. Also, the metric monitor allows users to check for website detailed analytics and overall this is a great tool.


  • Free Trial
  • Advanced $18,700/year
  • Professional $27,000/year
  • Expert $43,900/year

Website: Zabbix

#3) Nagios

Best for multiple OS monitoring.


[image source]

Nagios is an effective tool that makes it easier for users to manage service requests efficiently. This tool is also equipped with a problem response technique that allows you to fix website issues and make the work more efficient. The tool views infrastructure capabilities, making it easier for users to fix the response time.

The tool has a stable platform that ensures good working efficiency and it also has an extendable infrastructure that builds the working structure fast.


  • This tool is equipped with Windows monitoring, allowing users to manage analytics and extract data from the website.
  • Linux monitoring with Linux servers can easily manage a massive amount of requests.
  • Through the server monitoring feature, users can manage service requests and create data logs for the same.
  • The application monitoring feature helps to extract data from the application and manage traffic received from it.
  • The database monitoring feature of this application allows users to extract and operate on data simultaneously.
  • The Log monitoring feature manages all the logs and entries of data.
  • This tool manages metrics and protocols to generate reports.
  • It uses a powerful script API to perform operations easily.
  • Provides an entire view infrastructure to manage architecture and networks.
  • This tool has a fast detection technology to fix web page crashes and other issues.
  • It generates notifications and alerts that keep you updated with the server reports.


  • Linux monitoring.
  • Expendable architecture.


  • Complex UI.

Verdict: This tool is handy with a series of features that make it easier for users to manage reports, but it is a bit expensive compared to other tools.


  • Free trial
  • Number of nodes
    • (100,200,300,400,500 nodes) starts at $1995
    • Unlimited node license $19,995
  • Instance
    • Starts at $3995
    • 20+ instance license- contact sales
  • Phone Support
    • 5 calls $1,995
    • 10 calls $2,995

Website: Nagios

#4) Observium

Best for traffic monitoring and management.


Observium is a tool that allows you to monitor the server’s traffic and use API integration to enhance your work quality. This tool uses various accounting systems like IP SLA, Pseudowire, and class-based QoS metrics.


  • Receive real-time updates and fixes.
  • Unlimited number of monitored devices, sensors, and ports, allowing you to work with multiple devices quickly.
  • This tool has a full auto-discovery feature, making it easier to obtain metrics and maintain a record of supported devices.
  • Attain network mapping through a series of discovery protocols.
  • Advanced alerting feature like Syslog, state, and threshold altering.
  • Amazing feature of a traffic accounting system to create a log and maintain records.

Verdict: This handy tool with terrific features helps users to work efficiently and manage traffic data effectively.


  • Free
  • Professional $280/year
  • Enterprise $1400/year

Website: Observium

#5) Checkmk

Best for being used as a powerful automation tool.


Checkmk has various features which enhance the quality of working. The features include auto-discovery, which allows users to discover the devices in nearby regions. Auto-configuration and automated agent updates will enable you to automate all basic operations. It offers automatic monitoring for various infrastructures, including dynamic and temporary ones.

Checkmk tool has a powerful API integration with various systems like ITOM, which makes your work more accessible, and with dynamic dashboards, you remain updated all the time.


  • Enables rapid deployment, making the server faster and more efficient.
  • Launches all the reports in the least latency time.
  • Get a quick installation from a single package.
  • Unique auto-discovery feature identifies over 90% of devices in the surrounding.
  • Set intelligent alarms which alert you when the mentioned parameters are achieved.
  • Increase the scalability of your product and business.
  • Access multiple server hosts at a time over a hundred thousand.
  • This tool uses instance modulation and distributes architecture for effective management.
  • This tool has minor minimal requirements and works quickly.
  • The most helpful automation feature automates basic operations easily.

Verdict: This is a handy tool with a series of features that make automation much easier for you, and this tool has considerable pricing.


  • Standard $904/year (including tax)
  • Standard Group $1773.10/year (including tax)
  • Managed Services $1773.10/year(including tax)

Website: Checkmk

#6) EventSentry

Best for provides accurate time event log monitoring along with descriptive email alerts.


EventSentry is a tool that provides metrics reports as per your requirements and this is the primary reason why it is licensed based on per host. This tool allows you to analyze multiple aspects of the server. It will enable you to collect all the required information to process data and produce efficient results.


  • This tool provides users with real-time alerts, making it easier for them to overcome issues and fix them at the earliest.
  • Provides flexible dashboards to enhance the workflow.
  • Effective restful Reporting API, carrying out integration and data sync easier.
  • Provides event log normalization and correlation.
  • Store unlimited data for the same price.
  • This tool is cheap as compared to other tools in the league.
  • Provides users with email and phone support.

Verdict: This is a handy tool with wonderful features, and this tool has low prices compared to other tools.


  • Free Demo
  • One full license: $85
  • Add Ons
    • Netflow License
    • 1 license : $1,299
    • 2-hour deployment $250

Website: EventSentry

#7) Riemann

Best for in-depth insights on your server.


Riemann is an open-source tool that users can easily alter as per their requirements, and this tool requires minimal device configurations to work efficiently. This tool alerts you at the earliest when the server faces issues and provides you with direct access to resolve the issue.


  • Interactive interface that displays all the required data in one go.
  • Provides users with features like Phone, SMS, and email alerts for effective working.
  • Provides graphs that make it easier to comprehend complex reports.
  • This tool integrates various protocols, making the entire communication compact, fast wire, and portable.
  • This tool allows you to specify a series of query states and run them on the database for the best results.

Verdict: This tool is a good tool as it allows you to run various codes and specify different commands, making the work easier by automating tasks.

Pricing: Free

Website: Riemann

#8) Sensu

Best for an interactive UI that allows users to make reports presentable.


Sensu comes in two versions: the standard version and the Sensu Go version, which focuses on providing users with different requirements. This tool provides effective health monitoring strategies, as this tool has excellent custom script implementation features. It integrates plugins and collects metric information to create well-detailed reports.


  • Various integrated features make working easier, like Splunk, ElasticSearch, ServiceNow, and many more.
  • It is highly secure, with advanced features like an Active directory.
  • It automates the process of agent identification, which helps to create a list of all users.
  • This tool has external PKI verification with CRL Support.
  • It increases the working and scalability using an efficient enterprise data store.
  • This tool focuses on enhancing the monitoring workflow to configure the service-based store.

Verdict: This tool is an amazing tool as it has many features and offers enhanced security support. It helps users to manage their data store and present data metrics efficiently.


  • Free
  • Pro $3/node/month (minimum 200 nodes)
  • Enterprise $5/node/month (minimum 300 nodes)
  • Sensus Plus
    • Free
    • Pro $5/node/month (minimum 200 nodes)
    • Enterprise $8/node/month (minimum 300 nodes)

Website: Sensu

#9) Icinga

Best for extensible website scalability.


Icinga is a tool that allows you to collect all the traffic data and analyze them to present them in the best visual manner. This tool will enable you to consider the performance factors using the metric data and alert users when a pattern occurs in data. Icinga also helps you set insights to get specific reports on certain servers.


  • This tool uses dynamic data processing that helps users to make their business more scalable and manage a massive amount of data points.
  • It has an event-driven structure that allows users to scale and make their business extensible.
  • It has a great community that allows users to interact with other developers for consistent growth.
  • This is an open-source tool to change the code as per their requirements.
  • This tool provides in-depth insights and real-time notifications on server upgrades.
  • This tool has eye-opening visuals and analytics, making data much more presentable.

Verdict: This tool is handy, and the best thing about this tool is the presence of so many visual techniques, which makes it easier to comprehend and understand data.

Pricing: Contact sales

Website: Icinga

#10) OpenNMS

Best for best fault management and effective results techniques.

OpenNMS - open source monitor

OpenNMS is a tool that provides business service hierarchy and impact analysis that allows you to study the event’s impact on the server’s traffic. This tool provides users with support for customers, including email and SMS alerts. It also offers duty schedules, making it easier to manage work efficiently, and can be integrated with Jira, TSRM, RT, and Drools.


  • This tool has a fault management section to find flaws in the website and handle them efficiently.
  • Performance management features help analyze and boost performance.
  • An extensive network and topology discovery for enhanced output.
  • The Route Monitoring feature allows users to monitor traffic and manage it efficiently.
  • The distributed monitoring features that allow users to monitor multiple servers.
  • This tool provides network traffic analysis, making it easier to draw out conclusions from reports.

Verdict: This tool has a series of features that makes it an all-rounder tool with a bunch of extra features which facilitate advanced operations. It also provides features, hardware, and topology suggestions for efficient results.


  • Maintenance
    • Starts at $6,000
  • Prime Support
    • Starts at $20,400
  • PostgreSQL: included
    • Starts at $1,200
  • Ultra Support
    • Starts at $48,000
  • PostgreSQL: included
    • Starts at $1,200
  • Support Adons
    • 24×7 Emergency Support: $15,000
    • Additional Support Contacts: $2,500 each

Website: OpenNMS

#11) Cacti

Best for a very interactive User Interface.

Cacti - open source monitor tool

Cacti personalize their dashboard and servers as per their requirements. It also helps users add multiple plugins, data managers, and frameworks to the network. This tool has a series of role-based user and domain management features that make it easier for users to run theming engines and set themes in the dashboard.

This tool can be an excellent choice for setting up complex installations and LAN-sized setups.


  • This tool has a significant fault management framework to efficiently locate and fix issues.
  • The network graphing solution supports users to develop advanced graphs with RRD tool data storage.
  • Fault-free data collection framework for enhanced efficiency.
  • Advanced automated templates for faster workflow.
  • This tool also offers multiple data acquisition methods, making it easier to allocate data.
  • This tool has a series of plugins that make it easier to embed various features in the network.

Verdict: This is a good tool with features that make users work efficiently and allow them to customize the theme of the dashboard as per their requirements. So overall, this is a good choice.

Pricing: Free

Website: Cacti

#12) LibreNMS

Best for mobile-based monitors.

LibreNMS1 - open source monitor

[image source]

LibreNMS uses distributed polling techniques which allow users to scale their business horizontally by providing extensive device support and accessibility. This tool has a mobile-friendly interface and is compatible with Android and iOS.


  • Equipped with automatic discovery to locate nearby devices.
  • Customizable alerting feature helps to set alerts.
  • Provides users with complete control of API Access to manage their work efficiently.
  • Generate bandwidth bills for your network ports.
  • This tool ensures that your application remains up to date.
  • This tool is compatible with both iOS and Android devices.

Verdict: This tool has various features, but it is suitable only for users looking for a mobile-based network monitor.

Pricing: Donationware

Website: LibreNMS

Other Notable Tools

#13) Netdata

It is a handy open-source application as it provides accurate time visualization and its auto-deployment features make it easier for users to overcome deployment bugs. This tool searches through the entire architecture extract results and will enable you to generate instant charts from the analytics data received.

Pricing: Free

Website: Netdata

#14) M/Monit

This tool is comparatively easy to set up. This tool has an amazing and user-friendly UI that allows beginners to work comfortably on this application. This tool uses advanced charts, making it easier to express in-depth insights. It also has better uptime for your server as compared to other tools.


  • Five hosts – €65
  • Ten hosts- €129
  • Enterprise: contact sales

Website: M/Monit

#15) Pandora FMS

This tool has advanced histogram graph modules, making data comparison easier as users can quickly compare with the well-aligned graphical data. The tool also allows you to connect various plugins to the server and automate a series of processes. Pandora FMs consists of a remote check feature, making it easier for users to access the application remotely.

Pricing: Free

Website: Pandora FMS

#16) AppNetaPathTest

This tool provides network paths that ensure end-to-end network efficiency, including performance, health, and availability. It also offers the most advanced network workflow to the users, making it easier to manage the work.

Pricing: Free

Website: AppNetaPathTest

#17) LogRhythm NetMon Freemium

This tool is equipped with advanced threat detection techniques, making it easier for users to detect a series of threats and make their server safe. This open-source monitor tool can be integrated with various applications and is embedded with Tensor Mist AI, allowing them to scale applications with mathematical calculations.

Pricing: Freemium

Website: LogRhythm NetMon Freemium

#18) Munin

This tool allows you to generate real-time alerts as it checks through the server after a small interval to ensure safety, also this tool is highly scalable. Munin has a flexible and extensible workflow that makes it easier for users to work without much trouble and even helps them advance their working patterns.

Pricing: Free

Website: Munin

#19) ntopng

This tool has advanced network traffic protocols and a series of layer management protocols that safeguard your server. This tool generates long-term reports and metrics of the server, which makes it easier to comprehend the system’s overall performance. The tool shows real-time traffic along with active hosts on the server.

Pricing: Free

Website: ntopng

#20) NetXMS

This tool is highly scalable, i.e., you can work with massive networks with this tool, and the highly customizable feature of this tool makes it easier to customize the device as per requirements. The application’s cross-platform and security protocols make it a great pick.

Pricing: Free

Website: NetXMS


Network monitor tools help users conduct a series of checks on the servers and fix various issues to achieve better performance at work. By using these tools, users can enhance their workflow too.

Therefore, in this article, we have discussed different network monitors, among which Prometheus and Zabbix are the best open-source server monitor tools.

Research Process:

  • We spent a total of 42 hours researching and writing this article. We did this so that you can get summarized and insightful information on the best open source monitor applications.
  • Total apps researched: 35
  • Total apps shortlisted: 20
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