Channel-Based communication is available since release 11.0 as an experimental functionality for publish-subscribe communication between WL sessions or with external systems.

Functionality works well between WL sessions, but when trying to send messages through external systems, I was unable to make this work.

myChannel = CreateChannel["demo", Permissions -> "Public"]
(*ChannelObject["https://channelbroker.wolframcloud.com/users/[email protected]/demo"]*)

listener = ChannelListen[myChannel];

ChannelSend[myChannel, <|key -> "test"|>]
(*Message Successful*)

Prepare command for curl (or web browser)
url = URLBuild[listener["URL"], {"operation" -> "send", "Message" -> "yet another message"}]


(*Sending Message through the Mathematica Session works*)
(*message ID*)

When trying through terminal with curl URL, or through the web browser, the following message is displayed:

403 Forbidden

  • $\begingroup$ I can replicate this problem. It happens just as you have described. $\endgroup$
    – C. E.
    Commented Feb 2, 2017 at 0:38

1 Answer 1


When copying a URL to external programs, make sure that you are using Edit > Copy As > Plain Text (Cmnd-Shift-C on Mac)... or otherwise remove the line continuation characters ("\") that the Front End inserts in the copied text.

As yet another trick, you can execute:


... and then click the output link. That will use the correct URL in your default web browser.

  • $\begingroup$ Dear Igor, thank you. I've got some extra questions about channel networks that I wouldwant to ask you. Please can you contact me via the wolfram community if you can $\endgroup$
    – Zviovich
    Commented Feb 3, 2017 at 17:37

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