Looking for a OpenNMS Horizon / Meridian alternative? OpenNMS Horizon / Meridian is built for larger networks that want protocol-level topology discovery inside a full monitoring platform. OpenNMS Horizon / Meridian's trade-off: a full monitoring platform, so the topology arrives with alerting, performance collection, and provisioning to configure and run. These are the best OpenNMS Horizon / Meridian alternatives for network discovery, topology visualization, and living documentation, starting with the one we build, Scanopy.
The best OpenNMS Horizon / Meridian alternatives
Scanopy Our pick
A dedicated network documentation tool: one scan produces four switchable views (L2 physical, L3 logical, workloads, and applications) plus per-host service detection, at flat pricing regardless of host count, with a free, self-hostable Community edition.
NetBox
NetBox is for network and automation teams building a structured source of truth to drive Ansible, Nornir, or Terraform.
Scanopy vs NetBox, head to head →phpIPAM
phpIPAM is for teams that plan and assign address space, including ranges reserved before anything is deployed.
Scanopy vs phpIPAM, head to head →Observium is for teams that want autodiscovering SNMP monitoring across mixed vendors and can treat mapping as a per-device view.
Scanopy vs Observium, head to head →Zabbix
Zabbix is for teams that want one free monitoring platform across servers, applications, and network devices.
Scanopy vs Zabbix, head to head →Auvik
Auvik is for MSPs who need monitoring, alerting, and network maps in one cloud-managed platform.
Scanopy vs Auvik, head to head →NetBrain
NetBrain is for large enterprises that need network maps integrated with automation and troubleshooting workflows.
Scanopy vs NetBrain, head to head →SolarWinds Network Topology Mapper is for enterprise teams that standardize on Microsoft tools and need Visio-native network diagram exports.
Scanopy vs SolarWinds Network Topology Mapper, head to head →Domotz
Domotz is for cost-conscious MSPs who need monitoring, remote access, and basic network maps at a published price.
Scanopy vs Domotz, head to head →ManageEngine OpManager is for mid-market IT teams that want monitoring and visualization at a lower per-device cost.
Scanopy vs ManageEngine OpManager, head to head →PRTG Network Monitor is for teams already running Paessler for monitoring who want status dashboards alongside their sensor data.
Scanopy vs PRTG Network Monitor, head to head →LibreNMS
LibreNMS is for teams with Linux skills that want free, self-hosted monitoring with basic topology visualization.
Scanopy vs LibreNMS, head to head →NetDisco
NetDisco is for network teams that want free, open-source Layer 2 topology discovery and device tracking.
Scanopy vs NetDisco, head to head →Faddom
Faddom is for enterprise IT teams mapping application dependencies for data center migrations and cloud transitions.
Scanopy vs Faddom, head to head →OpenNMS Horizon / Meridian alternatives compared
How OpenNMS Horizon / Meridian and each alternative compare on discovery, the four topology views (L2, L3, workloads, applications), service detection, pricing, and licensing.
| ToolProduct name and link to vendor site | DiscoveryProtocols used to find devices and map connections | Network ViewsWhich topology views the tool produces from discovery. L2 Physical switch ports and links L3 Subnets, VLANs, routing Workload VM/container host nesting Application Service-dependency / app grouping Yes supported Tag ? unverified Greyed not supported | ServicesNo No service awareness Basic Common port detection Yes Application-level fingerprinting | PricingStarting price or pricing model | Open SourceOSI OSI-approved open source license Source available Source code available, restricted license No Proprietary |
|---|---|---|---|---|---|
| OpenNMS | SNMP CDP LLDP ICMP [52] | Basic | Free (Horizon); Meridian subscription [55] | OSI AGPL-3.0 | |
| Scanopy | SNMP LLDP CDP ARP TCP/UDP | Yes250+ types | Starts at $11.99 monthly, unlimited hosts | OSI AGPL-3.0 | |
| NetBox | ICMP SNMP SSH/CLI | No | Cloud and Enterprise: contact sales [42] | OSI Apache-2.0 | |
| phpIPAM | SNMP ICMP [47] | No | Free | OSI GPL-3.0 | |
| Observium | SNMP CDP LLDP [50] | No | Free (Community); Professional subscription [51] | OSI QPL | |
| Zabbix | SNMP ICMP | No | Free | OSI AGPL-3.0 | |
| Auvik | SNMP CDP LLDP ARP [1] | Basic [2] | Per-device (contact sales) | No | |
| NetBrain | SNMP CDP LLDP ARP SSH/CLI | No | Enterprise (contact sales) | No | |
| SolarWinds NTM | SNMP WMI CDP LLDP ICMP [3] | No | Perpetual ~$1,570 (subscription shift unclear) [44] | No | |
| Domotz | SNMP ARP ICMP CDP LLDP mDNS NetBIOS [5] | Basic [6] | $1.50/device/mo [7] | No | |
| ManageEngine OpManager | SNMP CDP LLDP ARP [8] | No | From $95/yr (10 devices) [9] | No | |
| PRTG | SNMP WMI ICMP [13] | No | Free to 100 sensors, then $200-$1,642/mo [4] | No | |
| LibreNMS | SNMP CDP LLDP [10] | No | Free | OSI GPL-3.0 | |
| NetDisco | SNMP CDP LLDP ARP [12] | No | Free | OSI BSD | |
| Faddom | NetFlow/sFlow [23] | Basicapp dependencies [23] | Free up to 50 servers then from $19,000/yr [24] | No |
Why Scanopy is a strong OpenNMS Horizon / Meridian alternative
OpenNMS is the closest tool on this list to Scanopy on discovery. Its Enhanced Linkd (Enlinkd) daemon runs five link-discovery methods by default: Bridge, CDP, IS-IS, LLDP, and OSPF, and it draws a CDP or LLDP edge only where both devices report each other. That is real protocol-level topology discovery, not a hand-placed diagram, and it covers routing topology as well as Layer 2. Scanopy discovers over the same family of protocols and adds ARP and MAC forwarding tables.
The difference is scope on both sides. OpenNMS is a full network management platform: alerting, performance collection, provisioning, and event correlation, with topology as one view inside it. Scanopy does documentation only, and covers two things OpenNMS does not: per-host service detection across hundreds of service types, and workload and application views showing VMs and containers nested in their hosts and services grouped by the application they make up. It also gets the map out, as exports (image, self-contained HTML, wiki markup, CSV), an embedded live map in a wiki or intranet, or a read-only link that stays current.
Both are AGPL-3.0 and self-hostable, so licence is not the deciding factor. Choose OpenNMS if you want topology inside a platform that also monitors, and you have the capacity to run it. Choose Scanopy if you want documentation that stands on its own, covers workloads and applications alongside L2 and L3, and can be handed to someone as a map. Scanopy runs alongside a monitoring platform rather than replacing one, so running both is a coherent setup.
Frequently asked questions
What is the best alternative to OpenNMS Horizon / Meridian?
The right alternative depends on what you use OpenNMS Horizon / Meridian for. If you want automatic network discovery with living L2, L3, workload, and application views and per-host service detection, Scanopy is the closest dedicated alternative: flat pricing regardless of host count, plus a free, self-hostable Community edition. OpenNMS Horizon / Meridian itself remains the better choice when you specifically need larger networks that want protocol-level topology discovery inside a full monitoring platform.
Is there a free or open-source OpenNMS Horizon / Meridian alternative?
Yes. Scanopy, NetBox, phpIPAM, Observium, Zabbix, LibreNMS, and NetDisco are open-source (OSI-licensed). Scanopy's Community edition is free to self-host under AGPL-3.0 and produces the full L2, L3, workload, and application views; the paid plans add cloud hosting and support at flat pricing.
Why do teams look for a OpenNMS Horizon / Meridian alternative?
One documented limitation: a full monitoring platform, so the topology arrives with alerting, performance collection, and provisioning to configure and run. Scanopy produces an up-to-date visual map of what is on the network without a separate monitoring platform, which is why it is compared against OpenNMS Horizon / Meridian.
Comparing just these two? See the focused Scanopy vs OpenNMS Horizon / Meridian head-to-head. For all 13 tools side by side, see the full network documentation tools comparison.
Sources
[2] Auvik - Can Auvik discover services on my network?
[3] SolarWinds - Network Topology Mapper
[4] Paessler - PRTG Pricing
[5] Domotz - Agentless Network Discovery for MSP Client Onboarding
[6] Domotz - Device TCP/UDP Ports/Services Discovery
[7] Domotz - Pricing
[8] ManageEngine - Discover Networks
[9] ManageEngine - OpManager Editions
[10] LibreNMS - Auto-Discovery
[12] NetDisco - Documentation
[13] Paessler - PRTG System Requirements
[23] Faddom - Agentless Application Dependency Mapping
[24] Faddom - Pricing
[42] NetBox Labs - Pricing (Cloud and Enterprise contact sales)
[44] SolarWinds NTM - Pricing (TrustRadius)
[47] phpIPAM - Open source IP address management (GPL-3.0)
[50] Observium - Autodiscovery via CDP, LLDP, FDP, EDP and OSPF neighbours
[51] Observium - Subscribe: Community vs Professional editions
[52] OpenNMS - Enhanced Linkd (Enlinkd): five link-discovery methods enabled by default
[55] OpenNMS - Meridian subscription pricing
Started as a homelabber, now deep in SNMP MIBs, Layer 3 topology, and service fingerprinting - building the network documentation tool I wished existed.