Softwr

Networking · head to head

Eclipse Mosquitto vs OPNsense

Eclipse Mosquitto logo

Eclipse Mosquitto

Networking

Small, EPL-licensed MQTT broker that runs on hardware other brokers cannot

From
Free
Rated
-
Full reviewWebsite
OPNsense logo

OPNsense

Networking

FreeBSD-based firewall and routing platform with weekly updates and a full configuration API

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Eclipse Mosquitto there is no clustering: Mosquitto is a single process, so high availability means building your own failover and accepting session loss on switchover.; OPNsense throughput depends entirely on hardware you selected yourself, and intrusion prevention at multi-gigabit rates will saturate a machine that handled plain firewalling fine, with no vendor sizing commitment to fall back on.
  • They diverge on capability: Eclipse Mosquitto covers MQTT 5.0 support, OPNsense covers Stateful firewall on pf.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Eclipse Mosquitto and OPNsense actually diverge.

Attributes where Eclipse Mosquitto and OPNsense differ
AttributeEclipse MosquittoOPNsense
PlatformsLinux, Windows, macOS, Dockerx86-64 appliances, Virtual machines, Deciso hardware

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), user rating (Not yet rated), category (Networking).

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 Eclipse Mosquitto

  • MQTT 5.0 support
  • Very small footprint
  • Bridging
  • WebSockets listener
  • Command line clients
  • Dynamic security plugin

Only in OPNsense

  • Stateful firewall on pf
  • VPN suite
  • Suricata IDS and IPS
  • Full configuration API
  • High availability
  • Weekly update cadence

What people use each for

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

Eclipse Mosquitto

  • A home or building automation stack where the broker must run on the same small computer as everything elsenot OPNsense
  • An industrial gateway that buffers local telemetry and bridges selected topics to a cloud brokernot OPNsense
  • Local development and testing of MQTT clients without provisioning a cloud IoT servicenot OPNsense
  • An air-gapped deployment where a broker with no licence server and no phone-home behaviour is a requirementnot OPNsense

OPNsense

  • Replacing a small business firewall appliance whose renewal quote exceeded the cost of the hardwarenot Eclipse Mosquitto
  • Branch offices where the firewall configuration must be produced by Ansible rather than by handnot Eclipse Mosquitto
  • Sites that need WireGuard and intrusion prevention on the same box without separate feature licencesnot Eclipse Mosquitto
  • A homelab or lab network needing VLAN routing, multi-WAN and DNS filtering on one machinenot Eclipse Mosquitto

Where each one falls short

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

Eclipse Mosquitto

  • There is no clustering: Mosquitto is a single process, so high availability means building your own failover and accepting session loss on switchover.
  • Persistence is a local file rather than a replicated store, so a disk failure or an unclean shutdown can lose retained messages and queued QoS traffic.
  • Practical capacity is a few thousand concurrent clients on typical hardware, so a growing device fleet eventually forces a migration to a clustered broker.
  • The Eclipse Public Licence is weak copyleft rather than permissive, which some legal teams treat as a blocker when embedding the broker in a shipped commercial product.
  • There is no commercial support to buy from the project, so production incidents rely on community mailing lists or on paying a third party who happens to know the codebase.

OPNsense

  • Throughput depends entirely on hardware you selected yourself, and intrusion prevention at multi-gigabit rates will saturate a machine that handled plain firewalling fine, with no vendor sizing commitment to fall back on.
  • The weekly update cadence is good for security but means more change events than a team used to annual appliance firmware, and occasional regressions reach production installations.
  • FreeBSD underneath limits driver support compared with Linux, so recent network cards and some virtualisation drivers can be unsupported or slow.
  • The plugin ecosystem is uneven in quality; some plugins are maintained by a single contributor and can lag a major release, breaking a function you depended on.
  • Community support is a forum, so an outage at two in the morning on the free edition is your problem alone unless you bought the business subscription in advance.

Pricing, plan by plan

Eclipse Mosquitto

Free
  • Eclipse MosquittoFree
    • Eclipse Public License 2.0 with Eclipse Distribution Licence
    • MQTT 5.0, 3.1.1 and 3.1
    • No client or message limits beyond your hardware

OPNsense

Free
  • OPNsense Community EditionFree
    • MIT licence with no feature restrictions
    • All VPN, IDS and HA features included
    • Weekly updates and two major releases a year
  • OPNsense Business Edition$undefined/year
    • Stabilised update track lagging community releases
    • Commercial support from Deciso
    • Additional enterprise plugins and configuration backup

Which should you pick?

Choose Eclipse Mosquitto if

  • You need mqtt 5.0 support.
  • You want to start without paying.
  • You work on Linux, Windows, macOS, Docker.
  • You also want very small footprint.
Eclipse Mosquitto review

Choose OPNsense if

  • You need stateful firewall on pf.
  • You want to start without paying.
  • You work on x86-64 appliances, Virtual machines, Deciso hardware.
  • You also want vpn suite.
OPNsense review

Questions people ask

Is Eclipse Mosquitto or OPNsense better?
Neither clearly leads. Eclipse Mosquitto starts at Free and OPNsense at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Eclipse Mosquitto or OPNsense?
Eclipse Mosquitto starts at Free and OPNsense at Free.
Does Eclipse Mosquitto or OPNsense run on more platforms?
Eclipse Mosquitto runs on Linux, Windows, macOS, Docker. OPNsense runs on x86-64 appliances, Virtual machines, Deciso hardware.
Can I use Eclipse Mosquitto for free?
Both have a free tier, so you can try either at no cost before committing.
What is Eclipse Mosquitto best used for?
Eclipse Mosquitto is most often used for a home or building automation stack where the broker must run on the same small computer as everything else, an industrial gateway that buffers local telemetry and bridges selected topics to a cloud broker, local development and testing of mqtt clients without provisioning a cloud iot service, an air-gapped deployment where a broker with no licence server and no phone-home behaviour is a requirement. Of those, a home or building automation stack where the broker must run on the same small computer as everything else and an industrial gateway that buffers local telemetry and bridges selected topics to a cloud broker are not what OPNsense is typically brought in for.
What can Eclipse Mosquitto do that OPNsense cannot?
Eclipse Mosquitto covers MQTT 5.0 support, Very small footprint, Bridging, WebSockets listener. OPNsense covers Stateful firewall on pf, VPN suite, Suricata IDS and IPS, Full configuration API.

Answered from the vendors’ own pages

Eclipse Mosquitto: Can Mosquitto be clustered?

No. It is a single process. High availability requires an external failover arrangement you build yourself.

OPNsense: How is it different from pfSense?

It is a 2015 fork with an MIT licence, a fixed weekly release cadence, a complete configuration API and a different interface. Feature coverage is comparable; the release process and API are the real differences.

Eclipse Mosquitto: What licence is it?

Eclipse Public License 2.0 alongside the Eclipse Distribution License, a weak copyleft rather than a permissive licence.

OPNsense: Do I need the Business Edition?

Only if you want commercial support or a slower, stabilised update stream. No features are withheld from the community edition.

Eclipse Mosquitto: How many clients can it handle?

A few thousand concurrent connections on ordinary hardware; beyond that, use a clustered broker.

OPNsense: Can it handle a gigabit internet connection?

Plain firewalling on modest current hardware, comfortably. With Suricata inspection enabled, expect to need a considerably stronger CPU.

Eclipse Mosquitto: Does it support MQTT 5?

Yes, along with 3.1.1 and 3.1.

Share

Related pages

More on Eclipse Mosquitto

More on OPNsense

Keep looking

Other head to heads