I don't know how "proprietary" or "walled-garden" it is, but I can connect to slack using open-source "irssi" on linux. http://www.tricksofthetrades.net/2015/0

I don't know how "proprietary" or "walled-garden" it is, but I can connect to slack using open-source "irssi" on linux. http://www.tricksofthetrades.net/2015/09/10/slack-irssi-connection/ http://www.tricksofthetrades.net/2015/09/10/slack-irssi-conn... I feel like that has to diminish the walled-garden, proprietary weight at least a little bit if slack & irssi can communicate. And it works over SSL too. Once I started doing that, I didn't mind using slack. You have to "/ignore" certain server messages though or your whole screen will be spammed with them and you'll barely see the stuff people are saying.