[Update 2015-01-29]: added some details of the scenario in question.
Just to make sure: Do the licensen conditions allow to distribute and deploy the crossbar (crossbar.io, wamp, ...) stack in a commercial application?
Given that
Yes, I have looked at AGPL 3.0 but I have to admit that I am not sure if the answer to my question is plain 'yes' or 'no'.
I am also aware that mongodb uses it. From the mongodb licensing:
To make the above practical, we promise that your client application which uses the database is a separate work. To facilitate this, the mongodb.org supported drivers (the part you link with your application) are released under Apache license, which is copyleft free.
Note: if you would like a signed letter asserting the above promise please contact MongoDB, Inc.
If I understand correctly, in order to use crossbar.io library in our scenario, it is importtant that our proprietary server code is considered 'separate work'.
Is it?
Crossbar.io is licensed under the AGPL 3.0, the same license that e.g. MongoDB uses. The requirements of the AGPL 3.0 are listed in the license text.
Crossbar.io is also available under a commercial license as part of Crossbar.io Enterprise Subscription offered by Tavendo.
Note that connecting a WAMP client to Crossbar.io does not affect, impose requirements on or restrict the license of the client.
Disclaimer: I am original author of Crossbar.io and work for Tavendo.