Is there a mechanism to send messages/notifications to other users?

Does the Platform have such a feature or do you have a plan to work on it?
For example, I Approve a Contract in BPM, and everyone involved get a message that a Contract moves to other stage.
Or someone edits an entity that I created, so that I want to receive a notification about this action, and write a direct message to that person (some kind of a chat, maybe).

The platform contains only a very simple mechanism of sending messages to currently active users. It is available to administrators in the User Sessions screen. The message is appeared on the recipient’s screen on the next ping request, which is performed three times per HTTP session timeout (set by the cuba.httpSessionExpirationTimeoutSec app property), i.e. not immediately.

We also have some indefinite plans about implementing the messaging and chat functionality in the form of an optional application component.

Hi,

additionally to what Konstantin said, i created a blog post a while ago: async event handling in CUBA where the last part of the blog post shows an implementation of what you described (although it is not real time and it is just a receive message inbox kind of a thing).

You can see the example code here: https://github.com/mariodavid/cuba-example-application-events

Bye
Mario