Unfortunately there are no such modules at the moment.

If the external app is your own development I suggest use the other way around: control Aximmetry from the app via HTTP, like described at  https://my.aximmetry.com/forum/postdetails/16-how-can-i-control-my-aximmetry-scene-from
(it requires the Broadcast Edition)

Has anything changed on this, or offering any other communication than XML, like little JSON?

Yes, the newer versions contain the HTTP Request module.
(Please note that it requires the Broadcast Edition.)
An example can be found in  [Tutorials]:Lower Thirds\Crawl_RSS_Vertical_Subtext.xcomp

Regarding Aximmetry's own HTTP control interface, we do not plan to enable JSON at the moment.

I was thinking  that HTTP Request module can be used in professional and Broadcast Editions, Is this correct?

No, in our current licensing structure it's only available in Broadcast.

• Aximmetry HTTP command interface is available from the Professional Edition. (ver. 2020.6.0)
  Is it true? Where to find this module?

Hi,

Yes, it's true. But you might mix up two different things here.

a) HTTP command interface is not a module, it's a service of Aximmetry through which you can control your scene from an external app. On this please consult
https://my.aximmetry.com/forum/postdetails/16-how-can-i-control-my-aximmetry-scene-from 

b) Connecting to an URL from Aximmetry via HTTP in order to retrieve some data. The module (node) that implements this is called "HTTP Request". Please check the example
[Tutorials]:Lower Thirds\Crawl_RSS_Vertical_Subtext.xcomp