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Networking · head to head

Eclipse Mosquitto vs Solace PubSub+

Eclipse Mosquitto logo

Eclipse Mosquitto

Networking

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

From
Free
Rated
-
Full reviewWebsite
Solace PubSub+ logo

Solace PubSub+

Databases

Multi-protocol event broker sold as software, cloud service or a hardware appliance

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.; Solace PubSub+ no pricing is published at any tier, so evaluation requires a sales engagement before you can even judge whether it is in budget, and broker tier sizing determines cost in ways buyers frequently get wrong.
  • They diverge on capability: Eclipse Mosquitto covers MQTT 5.0 support, Solace PubSub+ covers Multi-protocol broker.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Eclipse Mosquitto and Solace PubSub+ actually diverge.

Attributes where Eclipse Mosquitto and Solace PubSub+ differ
AttributeEclipse MosquittoSolace PubSub+
Pricing modelOpen source, no licence feequote
PlatformsLinux, Windows, macOS, DockerLinux, Docker, Kubernetes, Cloud, Hardware appliance
CategoryNetworkingDatabases

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 Eclipse Mosquitto

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

Only in Solace PubSub+

  • Multi-protocol broker
  • Dynamic message routing
  • Hardware appliance
  • Event Portal
  • Guaranteed delivery
  • Mission Control
  • Topic hierarchies and wildcards
  • Kafka and MQ bridging

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 Solace PubSub+
  • An industrial gateway that buffers local telemetry and bridges selected topics to a cloud brokernot Solace PubSub+
  • Local development and testing of MQTT clients without provisioning a cloud IoT servicenot Solace PubSub+
  • An air-gapped deployment where a broker with no licence server and no phone-home behaviour is a requirementnot Solace PubSub+

Solace PubSub+

  • A bank building an event mesh across regions where a Java JMS application and an MQTT mobile client must share the same topic spacenot Eclipse Mosquitto
  • An exchange or trading platform with a latency budget that needs the hardware appliance rather than a software brokernot Eclipse Mosquitto
  • An airline distributing operational events to ground systems, aircraft and partner APIs over different protocolsnot Eclipse Mosquitto
  • A manufacturer bridging factory MQTT telemetry into an enterprise Kafka estate without writing translation servicesnot 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.

Solace PubSub+

  • No pricing is published at any tier, so evaluation requires a sales engagement before you can even judge whether it is in budget, and broker tier sizing determines cost in ways buyers frequently get wrong.
  • The free Standard edition has hard capacity and support limits, which makes it useful for development but means any real deployment triggers a commercial negotiation.
  • The proprietary SMF protocol gives the best performance and feature coverage, so teams that lean on it acquire real switching costs even though open protocols are supported.
  • Operating a self-managed high availability broker pair with disaster recovery is a specialist task, and Solace expertise is scarce in the hiring market compared with Kafka skills.
  • Event Portal and Mission Control are licensed as part of platform packages, so the governance tooling that makes an event mesh manageable is not simply included with the broker.

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

Solace PubSub+

Free
  • Software Event Broker StandardFree
    • Free for production within capacity limits
    • Single node, capped connections and queues
    • No vendor support
  • Solace Cloud$undefined/year
    • Managed brokers in tiers from ENT-250 to ENT-100K
    • Foundation, Accelerate and Scale platform packages
    • Fixed subscription or annual consumption drawdown
  • Software Enterprise self-managed$undefined/year
    • Deploy in your own Kubernetes, VMs or data centre
    • High availability and disaster recovery
    • Support with SLA
  • Hardware appliance$undefined/year
    • Purpose-built appliance with FPGA message offload
    • Deterministic low latency
    • Sold with support contract

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 Solace PubSub+ if

  • You need multi-protocol broker.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Cloud, Hardware appliance.
  • You also want dynamic message routing.
Solace PubSub+ review

Questions people ask

Is Eclipse Mosquitto or Solace PubSub+ better?
Neither clearly leads. Eclipse Mosquitto starts at Free and Solace PubSub+ at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Eclipse Mosquitto or Solace PubSub+?
Eclipse Mosquitto starts at Free and Solace PubSub+ at Free.
Does Eclipse Mosquitto or Solace PubSub+ run on more platforms?
Eclipse Mosquitto runs on Linux, Windows, macOS, Docker. Solace PubSub+ runs on Linux, Docker, Kubernetes, Cloud, Hardware appliance.
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 Solace PubSub+ is typically brought in for.
What can Eclipse Mosquitto do that Solace PubSub+ cannot?
Eclipse Mosquitto covers MQTT 5.0 support, Very small footprint, Bridging, WebSockets listener. Solace PubSub+ covers Multi-protocol broker, Dynamic message routing, Hardware appliance, Event Portal.

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.

Solace PubSub+: Is there a free version of Solace?

Yes, the Standard edition of the software event broker is free for production within capacity limits, with no vendor support.

Eclipse Mosquitto: What licence is it?

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

Solace PubSub+: Does Solace publish prices?

No. Cloud, software and appliance are all quoted, based on broker tier from ENT-250 to ENT-100K and licensing model.

Eclipse Mosquitto: How many clients can it handle?

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

Solace PubSub+: Why buy an appliance in 2026?

Deterministic low latency with message processing offloaded to hardware, which matters in capital markets and little elsewhere.

Eclipse Mosquitto: Does it support MQTT 5?

Yes, along with 3.1.1 and 3.1.

Solace PubSub+: Can it replace Kafka?

Not for log retention and stream reprocessing. It is stronger at multi-protocol routing and guaranteed delivery, and the two are often bridged.

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