Open-source enterprise network monitoring platform
OpenNMS has carved out a solid position in our best network monitoring tools roundup as a compelling open-source alternative to commercial solutions. The platform offers two distributions — Horizon for rapid innovation and Meridian for enterprise stability, both completely open source. You’ll find comprehensive fault, performance, and traffic monitoring capabilities that rival expensive proprietary tools.
Techradar reviewers spend several weeks researching each major IT platform in the market. We found that OpenNMS excels at handling large-scale networks, with Fortune 500 companies using it to monitor tens of thousands of devices. While LogicMonitor remains our pick for the best network monitoring tool of 2025, OpenNMS delivers exceptional value for teams with strong technical skills.OpenNMS: Features
OpenNMS packs an impressive array of monitoring capabilities that rival commercial platforms costing thousands more. You get comprehensive network discovery, fault detection, performance monitoring, and traffic analysis in a single platform.
The feature set is well-suited for large enterprises and technical teams who need deep customization options. While some competitors offer more polished interfaces, OpenNMS compensates with raw power and flexibility. At $44,100 annually for enterprise support, the pricing reflects the platform’s enterprise-grade capabilities.
Network discovery and auto-discovery
OpenNMS automatically discovers devices across your network using industry-standard protocols like SNMP, HTTP, and JDBC. You can configure discovery ranges and let the platform map your entire infrastructure without manual intervention. The system integrates with over 2,000 networking vendors, ensuring compatibility with your existing hardware.
Fault management and alerting
The platform excels at fault detection with intelligent path outage analysis. Instead of flooding you with alerts when a core device fails, OpenNMS sends a single notification for the root cause. You may also appreciate features like escalation policies and contact groups that ensure the right people get notified at the right time.
Performance monitoring and graphing
Real-time performance data collection covers everything from CPU utilization to custom metrics. OpenNMS generates comprehensive graphs that integrate beautifully with Grafana for advanced visualization. The system handles up to 300,000 data points per second, making it suitable for the largest enterprise networks.
Flow analysis and traffic monitoring
Built-in support for NetFlow v5/9, IPFIX, and sFlow provides deep traffic analysis capabilities. You can track bandwidth utilization, identify top talkers, and analyze traffic patterns across your entire network. This feature alone justifies the platform for many organizations.
Business service monitoring
OpenNMS maps network performance to business services, helping you understand how technical issues impact operations. You can create custom service definitions and track their health across multiple network components.
