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Manufacturing · head to head

Kepware Server vs VerneMQ

Kepware Server logo

Kepware Server

Manufacturing

Industrial connectivity server translating 150-plus PLC protocols into OPC UA, formerly KEPServerEX

From
On request
Rated
-
Full reviewWebsite
VerneMQ logo

VerneMQ

Databases

Erlang MQTT broker whose source is Apache 2.0 but whose official binaries need a paid subscription

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only VerneMQ has a free tier, so it costs nothing to try first.
  • Each has a real cost: Kepware Server the base server is the small part of the bill; driver suites are priced by protocol family, and a mixed-vendor plant buys several, which is how a connectivity layer alone reaches tens of thousands of dollars.; VerneMQ the official binaries and Docker images are not Apache 2.0 but sit under a EULA requiring a yearly commercial subscription, a distinction easy to miss and awkward to discover during a licence audit.
  • They diverge on capability: Kepware Server covers 150-plus device drivers, VerneMQ covers Erlang/OTP clustering.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Kepware Server and VerneMQ actually diverge.

Attributes where Kepware Server and VerneMQ differ
AttributeKepware ServerVerneMQ
Starting priceOn requestFree
Free tierNoYes
PlatformsWindows, LinuxLinux, Docker, macOS, Kubernetes
CategoryManufacturingDatabases

Identical on both: pricing model (quote), 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 Kepware Server

  • 150-plus device drivers
  • OPC UA server
  • IoT Gateway
  • DataLogger
  • Redundancy Master
  • Security Policies
  • Configuration API
  • Kepware Edge

Only in VerneMQ

  • Erlang/OTP clustering
  • MQTT 5.0 support
  • Plugin system
  • Backpressure handling
  • Bridge support
  • Metrics export
  • MQTT over WebSockets
  • Pluggable auth backends

What people use each for

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

Kepware Server

  • Feeding a historian from a mixed plant of Allen-Bradley and Siemens PLCs without writing per-protocol driversnot VerneMQ
  • Publishing CNC machine state from FANUC and Haas controls to an OEE system over MQTTnot VerneMQ
  • Bridging legacy serial Modbus devices into an OPC UA architecture during a phased controller replacementnot VerneMQ
  • Running redundant collection servers so a cloud analytics pipeline does not lose data during Windows patchingnot VerneMQ

VerneMQ

  • An industrial operator that wants an MQTT broker with predictable memory behaviour and no data integration features it will not usenot Kepware Server
  • A team building from source to stay strictly under Apache 2.0 terms with no vendor licence entanglementnot Kepware Server
  • A deployment needing custom authentication logic implemented as a plugin in Lua or over a webhooknot Kepware Server
  • An organisation that wants a broker maintained by a small European company rather than by a vendor that keeps changing licencesnot Kepware Server

Where each one falls short

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

Kepware Server

  • The base server is the small part of the bill; driver suites are priced by protocol family, and a mixed-vendor plant buys several, which is how a connectivity layer alone reaches tens of thousands of dollars.
  • KEPServerEX to Kepware Server 7 is a migration rather than an in-place upgrade, and driver entitlements do not always transfer cleanly, so budget for revalidating every channel.
  • The full driver portfolio is Windows-only; the Linux product, Kepware Edge, supports a subset of drivers and is subscription-licensed by tag count, so an edge-first architecture cannot simply reuse the Windows configuration.
  • Three names have been in circulation for the same lineage, and quotes, forum answers and integrator experience still mix KEPServerEX, ThingWorx Kepware Server and Kepware Server, which produces mismatched proposals.
  • It is a translation layer with no storage, contextualisation or visualisation of its own, so it is always an addition to a historian or platform purchase rather than a substitute for one.

VerneMQ

  • The official binaries and Docker images are not Apache 2.0 but sit under a EULA requiring a yearly commercial subscription, a distinction easy to miss and awkward to discover during a licence audit.
  • Octavo Labs is a very small company, so support depth, response times and the bus factor on the codebase are materially thinner than at HiveMQ or EMQ.
  • There is no data integration or rule engine layer, so routing messages into a database means writing and operating your own consumer service.
  • Operating an Erlang cluster requires runtime knowledge that most teams do not have and will use for nothing else in their stack.
  • There is no vendor-managed cloud offering, so every deployment is self-operated with the infrastructure and on-call cost that implies.

Pricing, plan by plan

Kepware Server

On request
  • Kepware Server$undefined/year
    • Base server as a perpetual licence with annual maintenance, or subscription
    • Driver suites priced by protocol family and bought separately from the server
    • Advanced plug-ins such as IoT Gateway, DataLogger and Redundancy Master licensed individually

VerneMQ

Free
  • Source buildFree
    • Apache 2.0 licensed source from GitHub
    • Full clustering and plugin capability
    • You compile and package it yourself
  • Binary packages and Docker images$undefined/year
    • Covered by the VerneMQ EULA, not Apache 2.0
    • Yearly usage subscription expected for commercial use
    • Official builds and Docker images
  • Commercial support$undefined/year
    • Evaluation, customisation and operations assistance
    • Custom development
    • Long-term maintenance agreements

Which should you pick?

Choose Kepware Server if

  • You need 150-plus device drivers.
  • You work on Windows, Linux.
  • You also want opc ua server.
Kepware Server review

Choose VerneMQ if

  • You need erlang/otp clustering.
  • You want to start without paying.
  • You work on Linux, Docker, macOS, Kubernetes.
  • You also want mqtt 5.0 support.
VerneMQ review

Questions people ask

Is Kepware Server or VerneMQ better?
Neither clearly leads. Kepware Server starts at On request and VerneMQ at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Kepware Server or VerneMQ?
VerneMQ has a free tier; the other does not. Paid plans start at On request for Kepware Server and Free for VerneMQ.
Does Kepware Server or VerneMQ run on more platforms?
Kepware Server runs on Windows, Linux. VerneMQ runs on Linux, Docker, macOS, Kubernetes.
Can I use VerneMQ for free?
Yes. VerneMQ has a free tier, so you can try it without paying. Kepware Server starts at On request.
What is Kepware Server best used for?
Kepware Server is most often used for feeding a historian from a mixed plant of allen-bradley and siemens plcs without writing per-protocol drivers, publishing cnc machine state from fanuc and haas controls to an oee system over mqtt, bridging legacy serial modbus devices into an opc ua architecture during a phased controller replacement, running redundant collection servers so a cloud analytics pipeline does not lose data during windows patching. Of those, feeding a historian from a mixed plant of allen-bradley and siemens plcs without writing per-protocol drivers and publishing cnc machine state from fanuc and haas controls to an oee system over mqtt are not what VerneMQ is typically brought in for.
What can Kepware Server do that VerneMQ cannot?
Kepware Server covers 150-plus device drivers, OPC UA server, IoT Gateway, DataLogger. VerneMQ covers Erlang/OTP clustering, MQTT 5.0 support, Plugin system, Backpressure handling.

Answered from the vendors’ own pages

Kepware Server: Is KEPServerEX discontinued?

The name is. KEPServerEX and ThingWorx Kepware Server have been unified into Kepware Server, currently version 7, and the older names are being retired.

VerneMQ: Is VerneMQ free?

The source is Apache 2.0 and free. The official binary packages and Docker images are covered by a separate EULA that expects a yearly fee for commercial use.

Kepware Server: Is a perpetual licence still available?

Yes for the Windows server, with annual maintenance. Kepware Edge on Linux is subscription-only.

VerneMQ: Is the project still maintained?

Yes. Octavo Labs AG in Zurich continues to publish 2.x releases, most recently in 2026.

Kepware Server: What drives the price?

The number and type of driver suites, not the number of tags on the Windows product. Kepware Edge is priced by tag count.

VerneMQ: Does it have a managed cloud?

No. Every deployment is self-hosted, with commercial support available from Octavo Labs.

Kepware Server: Can I evaluate it before buying?

Yes. The runtime works for two hours at a time without a licence, indefinitely, which is enough to prove connectivity but not to run production.

VerneMQ: How does it compare to EMQX?

Narrower in features and without a rule engine, but with a simpler licence story for source builds after EMQX moved to BSL.

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