- Home
- Alert Management Software
- OpenNMS
OpenNMS
Lewisville, Texas, United States
What it is
OpenNMS is an open-source platform for monitoring faults, performance, traffic, and alarms across local and distributed networks. It comes as Horizon, a free community distribution with newer features, and Meridian, a stable subscription version. Horizon releases frequently, and some features may not be production-ready. Data collection supports protocols and services such as SNMP, JSON, SQL, HTTP, VMware, and Prometheus. Traffic monitoring supports NetFlow v.5/9, IPFIX, and sFlow, with a stated capacity of 300,000+ flows per second. Minions can monitor remote devices and services unreachable by the Core, including behind firewalls or NAT when connected through ActiveMQ or Apache Kafka. Integrations include email, Slack, Mattermost, Jira, Grafana, webhooks, and a REST API. A Grafana plugin can display alarms, outages, KPIs, NetFlow views, and data aggregated across OpenNMS instances. Meridian subscriptions include support options and severity-based SLAs; standard coverage is 7 a.m. to 7 p.m. ET weekdays, with 24/7 emergency support as an add-on. Listed platforms include API, Linux, self-hosted, and web.
For and against
For
- Monitors faults, performance, traffic, and alarms.
- Supports NetFlow, IPFIX, and sFlow traffic monitoring.
- Minions extend monitoring to remote devices behind firewalls or NAT.
- Grafana plugin displays alarms, outages, KPIs, and traffic views.
Against
- Horizon features may not all be production-ready.
- Meridian subscriptions are limited per instance.
- 24/7 emergency support is an add-on.
- Support plans exclude several third-party products.
The verdict
OpenNMS offers a free community distribution alongside a stable subscription version, with tools for distributed monitoring and traffic analysis. Check Horizon's readiness caveat or Meridian's per-instance subscription and support limits against your needs.
Who it suits
It suits teams monitoring networks across local and remote sites, including environments where the Core cannot directly reach devices. Horizon may suit users who want a free community distribution and can accommodate features that may not be production-ready.
Plans and prices
Horizon
Community distribution · Releases early and often · Features may not all be production-ready
Read 7 Oct 2026 · opennms.com
Basic
2 Meridian Cores · Meridian Core Repository
Read 7 Oct 2026 · opennms.com
Standard
2 Meridian Cores · Up to 1000 Devices · Meridian Core Repository
Read 7 Oct 2026 · opennms.com
Essential
Up to 2 Meridian Cores and 10 Minions · Meridian Core and Minion Repository
Read 7 Oct 2026 · opennms.com
Premier
Up to 4 Meridian Cores and 25 Minions · Meridian Core, Minion, and Sentinel Repository
Read 7 Oct 2026 · opennms.com
Premier+
More than 4 Meridian Cores and more than 25 Minions · Core, Minion, and Sentinel Repository plus container images
Read 7 Oct 2026 · opennms.com
On the record
- Collection protocols
- Its data collection supports SNMP, JSON, WinRM, XML, SQL, JMX, SFTP, FTP, JDBC, HTTP, HTTPS, VMware, WS-Management, and Prometheus.opennms.com · read 7 Oct 2026
- Company
- The OpenNMS Group says it was founded in 2004 and provides services from headquarters near Research Triangle, North Carolina; its site contact address is in Lewisville, Texas.opennms.com · read 7 Oct 2026
- Distributed monitoring
- Minions monitor devices and services at remote locations that the OpenNMS Core cannot reach, including behind firewalls or NAT when connected through ActiveMQ or Apache Kafka.opennms.com · read 7 Oct 2026
- Integrations
- The FAQ lists email, Slack, Mattermost, custom scripts or webhooks, Jira, Remedy, TSRM, Grafana, and a REST API among integrations.opennms.com · read 7 Oct 2026
- Purpose
- OpenNMS is an open-source network monitoring platform for fault, performance, traffic monitoring, and alarm generation across local and distributed networks.opennms.com · read 7 Oct 2026
- Scaling and license limits
- OpenNMS states there is no built-in per-instance device or alarm limit, while Meridian subscriptions are limited per instance and each software instance requires a subscription.opennms.com · read 7 Oct 2026
- Security
- The company says its security program aligns with ISO 27001/27002, CCPA, and GDPR frameworks, and major Meridian versions receive third-party penetration testing and remediation before release.opennms.com · read 7 Oct 2026
- Support
- Meridian subscriptions include support options and severity-based SLAs; the listed standard coverage is 7 a.m. to 7 p.m. ET Monday through Friday, with 24/7 emergency support as an add-on.opennms.com · read 7 Oct 2026
- Support limits
- OpenNMS support plans do not cover Linux, PostgreSQL, Grafana, Cassandra, Kafka, or Elasticsearch as third-party products.opennms.com · read 7 Oct 2026
- Traffic monitoring
- It supports NetFlow v.5/9, IPFIX, and sFlow, with stated capacity of 300,000+ flows per second.opennms.com · read 7 Oct 2026
- Two distributions
- OpenNMS is available as Meridian, an optimized stable subscription version, and Horizon, a free community distribution with the newest features.opennms.com · read 7 Oct 2026
- Visualization
- The OpenNMS Grafana plugin can display alarms, outages, KPIs, NetFlow visualizations, and data aggregated from multiple OpenNMS instances.opennms.com · read 7 Oct 2026
- Zero-trust
- OpenNMS describes zero-trust configurations that use encryption within private networks and strong authentication between authorized parties.opennms.com · read 7 Oct 2026
