The easiest way to provide async communication in Axon.ivy is currently a REST service.
See the `ConnectivityDemos` for some examples:
![alt text][1]
REST has been a good choice in the past for many customers as it does not require 'upgrade' request capabilities. Which is often a problem in real world installations where request reaches the client over front-end websevers that could apply request restrictions. Not to mention that the standard IIS integration approach, documented in the Axon.ivyEngine docs, can not use websockets. This restriction comes from the AJP protocol used between IIS and ivy.
However, if you know your target installation environment well you can activate any tomcat compatible websocket servlet. To do so the servlet must be deployed registered in a web-fragemnt.jar. For an example download the 6.3 engine and examine the portal-chat-endpoint.jar within `ivy/webapps/WEB-INF/lib`. Actually, we had websocket endpoints registered in there (based on PrimePush + Atmoshpere). Atmosphere). But, experience in many customer environments taught us that, for a generic platform, it is better to have an approach that works in any environment. So push servlets turned out to be a bad option.
[1]: https://answers.axonivy.com/upfiles/connectivyDemosAsync.png