Axon and the Kafka module


I would like to improve my Axon PoC by using Kafka as an event bus.
The documentation at writes about an axon-kafka module that
needs to be included. As far I can tell this refers to the project at
However the only release is 4.0-RC2 released on 18 October 2018, more than a year ago.

I would like to know what the general idea/roadmap is behind the Axon Kafka extension. I would like to take advantage
of the Kafka ecosystem in the overall architecture. Kafka has nice tools and UI to give insight in the events.
Axon and Kafka seems to be a good fit. And I am actually wondering why Axon does not use Kafka by default as the
event bus. Wouldn’t this actually save work for the Axon team? Less code to write and maintain for the Axon team, right?
Or am I mistaken?

So now Axon is on version 4.2, while the Kafka extension for 4.0 has never been released. Should I look at Eventuate
instead if I want to use Kafka?

And, I know this is a bit off-topic, but currently the web UI for Axon is rather… limited in functionality.
Will this be improved a lot? Or does this have no priority?

Hi Robert,

sorry for the delayed response. Somehow this message escaped my attention.

Kafka is indeed a good match with Axon. We’re currently working on getting it production-ready. The delay was caused by the fact that the extension was initially developed by an external committer, who was unable to find the time to complete it. As we had our own priorities, it took a while for us to pick it up.

Although Axon and Kafka are a good match, the default in Axon is not an Event Bus, but rather an Event Store. Kafka as an Event Store simply doesn’t work (except for a few very specific cases). So it won’t help us save development time, unfortunately…

The UI is indeed relatively limited in AxonServer. We’re gradually improving it as we release new features. We’re also working on a redesign based on the design of our (soon to be released) Axon Cloud Console.




Hi Allard,

Thanks very much for your reply. I really appreciate it. I understand now how Kafka is inherently not directly suited as an event store, for example because of not being able to replay efficiently for event sourced entities and commit events. It’s good to hear the Axon team is thinking and working on usability of the webui and I look forward to see the cloud console and redesign.

Hi Robert,

Whilst traversing the forum I stumbled upon this request of yours.

As of end last year, I have released the RC3 of Axon’s Kafka extension.

It is purely still an RC because we want to let it have some playtime out there; the functionality it currently provides is however the set which will be included in the 4.0 release.

Added, the reference guide has been updated accordingly with the changed implementation of the Kafka extension.

Please let us know what you think about it’s current look and feel.

Any feedback on it is very, very much appreciated!


Steven van Beelen

Axon Framework Lead Developer