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Networking · head to head

Eclipse Mosquitto vs Splunk

Eclipse Mosquitto logo

Eclipse Mosquitto

Networking

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

From
Free
Rated
-
Full reviewWebsite
Splunk logo

Splunk

Networking

Turn Data Into Doing

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only Eclipse Mosquitto has a free tier, so it costs nothing to try first.
  • 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.; Splunk no prices are published on any plan; every model requires contacting sales for an estimate
  • They diverge on capability: Eclipse Mosquitto covers MQTT 5.0 support, Splunk covers Log aggregation.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

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

Attributes where Eclipse Mosquitto and Splunk differ
AttributeEclipse MosquittoSplunk
Starting priceFreeOn request
Pricing modelOpen source, no licence feequote
Free tierYesNo
PlatformsLinux, Windows, macOS, DockerWeb, Api
FoundedUnknown2003

Identical on both: 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 Splunk

  • Log aggregation
  • Real-time monitoring
  • Data visualization
  • Full-text search
  • Custom dashboards
  • Alert management
  • Anomaly detection
  • Log parsing

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

Splunk

  • Log search and analysis across infrastructurenot Eclipse Mosquitto
  • SIEM, SOAR and UEBA for a security operations teamnot Eclipse Mosquitto
  • Application performance and infrastructure monitoringnot Eclipse Mosquitto
  • Cloud, private cloud or on-premises deploymentnot 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.

Splunk

  • No prices are published on any plan; every model requires contacting sales for an estimate
  • Three separate pricing models, workload, ingest and entity, so the same deployment costs different amounts depending on which was signed
  • Ingest pricing bills on data volume, so cost tracks how much you log rather than how much value you get from it
  • Security, observability and platform are priced separately

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

Splunk

On request
  • Observability Cloud - Infrastructure$15/month
    • Infrastructure monitoring for per host/month pricing
    • Unlimited users and ability to scale to petabytes of data
  • Observability Cloud - App & Infra$60/month
    • App and infrastructure monitoring for per host/month pricing billed annually
  • Observability Cloud - End-to-End$75/month
    • End-to-end observability for per host/month pricing billed annually
  • On-Call$5/month
    • On-call management for per user per month pricing billed annually
    • Covers up to 10 seats

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 Splunk if

  • You need log aggregation.
  • You work on Web, Api.
  • You also want real-time monitoring.
Splunk review

Questions people ask

Is Eclipse Mosquitto or Splunk better?
Neither clearly leads. Eclipse Mosquitto starts at Free and Splunk at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Eclipse Mosquitto or Splunk?
Eclipse Mosquitto has a free tier; the other does not. Paid plans start at Free for Eclipse Mosquitto and On request for Splunk.
Does Eclipse Mosquitto or Splunk run on more platforms?
Eclipse Mosquitto runs on Linux, Windows, macOS, Docker. Splunk runs on Web, Api.
Can I use Eclipse Mosquitto for free?
Yes. Eclipse Mosquitto has a free tier, so you can try it without paying. Splunk starts at On request.
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 Splunk is typically brought in for.
What can Eclipse Mosquitto do that Splunk cannot?
Eclipse Mosquitto covers MQTT 5.0 support, Very small footprint, Bridging, WebSockets listener. Splunk covers Log aggregation, Real-time monitoring, Data visualization, Full-text search.

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.

Splunk: What is Splunk's pricing model?

Splunk offers activity-based, ingest, or workload pricing options depending on the product. Splunk Observability Cloud and AppDynamics use per-host or per-vCPU monthly pricing billed annually. Splunk Cloud Platform and Splunk Enterprise require custom quotes from sales.

Source
Eclipse Mosquitto: What licence is it?

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

Splunk: How much does Splunk Enterprise cost?

Splunk Enterprise pricing requires contact with sales. The vendor offers data-ingest or workload pricing options, supports unlimited users, and can scale to petabytes of data, but specific rates are not published online.

Source
Eclipse Mosquitto: How many clients can it handle?

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

Splunk: What are the differences between Splunk's pricing options?

Splunk offers multiple pricing models: ingest-based pricing charges according to data volume brought into the system; workload-based pricing charges based on computing resources consumed by workloads. Both models apply to Splunk Enterprise and Splunk Cloud Platform. Standard support is included with product purchases; premium support is available as an add-on.

Source
Eclipse Mosquitto: Does it support MQTT 5?

Yes, along with 3.1.1 and 3.1.

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