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Best Free Alternatives to PRTG Network Monitor
Stop paying $1,800+. Discover professional-grade tools that won't break your budget.
Category: MonitoringVerified for 2025
Top Recommended Replacements
Zabbix
FREEBest Enterprise-Grade Free Alternative
Why we like it
No 'sensor' limits; handles everything from SNMP to cloud and IoT; features advanced AI-driven anomaly detection.
Keep in mind
Initial setup is much more complex than PRTG; requires significant time to tune dashboards and alerts.
LibreNMS
FREEBest for Automatic Discovery
Why we like it
Zero-touch discovery of your entire network; superior interface compared to Nagios; supports a massive range of hardware vendors.
Keep in mind
Primarily focused on network infrastructure (SNMP); not as deep for application-level monitoring as PRTG.
Checkmk (Raw Edition)
FREEBest for Rapid Deployment
Why we like it
Incredibly fast 'rule-based' configuration; monitors thousands of services in minutes; very efficient on system resources.
Keep in mind
The Raw edition uses a different core than the Enterprise version; some visualization features are restricted to the paid tier.
WhatsUp Gold (Free Edition)
FREEBest for Small Networks (Device-Based)
Why we like it
Superior interactive network topology maps; much easier to visualize 'hops' than in PRTG; free for up to 10 full devices (not sensors).
Keep in mind
Licensing beyond 10 devices becomes expensive; Windows-only installation.
Icinga 2
FREEBest for Custom Automation
Why we like it
Modern, sleek web interface; highly extensible via a powerful REST API; excellent for large, distributed environments.
Keep in mind
Requires knowledge of its specific configuration language (DSL); steep learning curve for beginners.
Prometheus & Grafana
FREEBest for Modern Cloud Dashboards
Why we like it
The gold standard for modern observability; Grafana provides far better visual dashboards than PRTG's native maps.
Keep in mind
Not a 'traditional' network monitor; requires exporters to pull SNMP data from older hardware.
Observium Community
FREEBest for Visual Hardware Audits
Why we like it
Automated, beautiful graphing of every hardware metric; great for keeping track of device firmware and serial numbers.
Keep in mind
Community version lacks real-time alerting; updates are delayed compared to the professional version.
Netdata
FREEBest for Per-Second Real-Time Data
Why we like it
Instant, zero-config monitoring; provides 1-second granularity that PRTG cannot match out of the box.
Keep in mind
Stores data in RAM by default (short-term history); best used for live troubleshooting rather than long-term capacity planning.
Nagios Core
FREEBest for Infinite Extensibility
Why we like it
The most established tool in the industry; if a device exists, there is a Nagios plugin to monitor it.
Keep in mind
The web interface is severely dated; configuration is manual and involves editing many text files.
Cacti
FREEBest for Bandwidth Graphing
Why we like it
Unrivaled for long-term RRDtool-based traffic graphing; completely free and community-supported.
Keep in mind
Interface feels like the early 2000s; alerting capabilities are basic compared to modern platforms.
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