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Networking · head to head

Nebula vs OpenHAB

Nebula logo

Nebula

Networking

Certificate based overlay network from Slack, with identity and firewall rules carried in the certificate

From
Free
Rated
-
Full reviewWebsite
OpenHAB logo

OpenHAB

Smart Home

Open source automation software for your home

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Nebula the open source project has no user interface, no enrolment workflow and no revocation service, so certificate issuing, distribution and expiry become scripts you write and then have to keep working.; OpenHAB requires a 64-bit Java 21 JVM to be installed and maintained separately
  • They diverge on capability: Nebula covers Certificate carried identity, OpenHAB covers Vendor Agnostic.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Nebula and OpenHAB actually diverge.

Attributes where Nebula and OpenHAB differ
AttributeNebulaOpenHAB
Pricing modelOpen source, no licence feeopen-source
PlatformsLinux, macOS, Windows, iOS, Android, FreeBSDLinux, Windows, MacOS, Docker, Raspberry Pi
CategoryNetworkingSmart Home
FoundedUnknown2010

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Nebula

  • Certificate carried identity
  • Group based host firewall
  • Lighthouse discovery
  • Noise protocol encryption
  • Unsafe routes
  • Managed option

Only in OpenHAB

  • Vendor Agnostic
  • Rule Engine
  • 200+ Bindings
  • Local Processing
  • Z-Wave
  • Zigbee
  • MQTT
  • REST API

What people use each for

The jobs each tool is most often brought in to do.

Nebula

  • Flattening a network across several clouds and datacentres without VPC peering or route tablesnot OpenHAB
  • Very large fleets where a central policy service on the connection path is unacceptablenot OpenHAB
  • Environments that already run an internal certificate authority and want the network to use itnot OpenHAB
  • Replacing per host iptables rules with policy written against roles that follow the hostnot OpenHAB

OpenHAB

  • Self-hosted vendor neutral home automation hubnot Nebula
  • Bridging smart home devices from different manufacturers under one set of rulesnot Nebula

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Nebula

  • The open source project has no user interface, no enrolment workflow and no revocation service, so certificate issuing, distribution and expiry become scripts you write and then have to keep working.
  • Revoking a compromised host means distributing a blocklist entry to every other host and reloading them, which is a fleet wide operation rather than a click, and easy to get wrong under pressure.
  • Changing a host group membership means reissuing and redeploying its certificate, so policy changes are a deployment rather than a configuration edit.
  • There is no identity provider integration or single sign on in the open source version, so it maps well to servers and badly to a fleet of user laptops.
  • NAT traversal is best effort and hosts behind symmetric NAT need a relay configured deliberately, so connectivity failures show up as intermittent rather than immediate and are awkward to diagnose.

OpenHAB

  • Requires a 64-bit Java 21 JVM to be installed and maintained separately
  • Oracle Java is explicitly not recommended by the project because of potential licensing restrictions
  • The recommended hardware is a dedicated Raspberry Pi 4 or newer rather than shared hardware
  • Some version upgrades require additional manual steps run through a separate upgrade tool

Pricing, plan by plan

Nebula

Free
  • NebulaFree
    • Full functionality under the MIT licence
    • No host limit
    • You operate the certificate authority and lighthouses
  • Defined Networking$undefined/month
    • Hosted control plane and enrolment
    • Managed certificate lifecycle and revocation
    • Policy and DNS interface

OpenHAB

Free
  • Community EditionFree
    • Unlimited devices
    • 200+ bindings
    • Local control

Which should you pick?

Choose Nebula if

  • You need certificate carried identity.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, iOS, Android, FreeBSD.
  • You also want group based host firewall.
Nebula review

Choose OpenHAB if

  • You need vendor agnostic.
  • You want to start without paying.
  • You work on Linux, Windows, MacOS, Docker, Raspberry Pi.
  • You also want rule engine.
OpenHAB review

Questions people ask

Is Nebula or OpenHAB better?
Neither clearly leads. Nebula starts at Free and OpenHAB at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Nebula or OpenHAB?
Nebula starts at Free and OpenHAB at Free.
Does Nebula or OpenHAB run on more platforms?
Nebula runs on Linux, macOS, Windows, iOS, Android, FreeBSD. OpenHAB runs on Linux, Windows, MacOS, Docker, Raspberry Pi.
Can I use Nebula for free?
Both have a free tier, so you can try either at no cost before committing.
What is Nebula best used for?
Nebula is most often used for flattening a network across several clouds and datacentres without vpc peering or route tables, very large fleets where a central policy service on the connection path is unacceptable, environments that already run an internal certificate authority and want the network to use it, replacing per host iptables rules with policy written against roles that follow the host. Of those, flattening a network across several clouds and datacentres without vpc peering or route tables and very large fleets where a central policy service on the connection path is unacceptable are not what OpenHAB is typically brought in for.
What can Nebula do that OpenHAB cannot?
Nebula covers Certificate carried identity, Group based host firewall, Lighthouse discovery, Noise protocol encryption. OpenHAB covers Vendor Agnostic, Rule Engine, 200+ Bindings, Local Processing.

Answered from the vendors’ own pages

Nebula: Does it use WireGuard?

No. Nebula predates the common WireGuard mesh tools and uses the Noise protocol framework with its own certificate format.

OpenHAB: How much does openHAB cost?

openHAB is 100% open source and completely free to download, install, and use across all supported platforms.

Source
Nebula: Can I run it without Defined Networking?

Yes, entirely. Defined Networking sells the control plane conveniences, not the network itself.

OpenHAB: Are there any subscription fees for openHAB?

No, openHAB has no subscription fees. The software is free and released under an open source license for unlimited use.

Source
Nebula: How do I revoke a host?

Add its certificate fingerprint to the blocklist in the configuration of the other hosts and reload them. There is no online revocation check.

OpenHAB: How can I support openHAB?

While openHAB is free to use, the project accepts voluntary donations through the openHAB Foundation to support development and maintenance.

Source
Nebula: Is it a good fit for laptops?

Less so than the identity provider based tools. There is no single sign on, so every laptop needs a certificate issued and renewed by whatever process you build.

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