Standalone Slack with Firefox

I’ve been using Slack via Chrome Apps so I can get an app shortcut in GNOME and have a separate window. My main browser is Firefox though, so it’s always been annoying when people share links and I have to copy & paste to see it in Firefox. I don’t have to, but I prefer it. Especially when my teammates have a bunch of problems with video chat in Chrome and I have none of those issues using Firefox.

Yesterday Slack via Chrome Apps stopped working. It simply opens a new tab like a regular website everytime I open it via the shortcut. That was enough to finally push me to look for a pure Firefox solution, and I’m sharing the steps here.

Make a Desktop App

I followed the instructions here to create a dedicated profile for Slack. I’ve included the steps here that have been modified to be specifically for Slack.

1. First run Firefox with a specific profile (the -P parameter):

> firefox --class=Slack -P slack -no-remote https://yourown.slack.com

You should then see a window like the one below:

2. Click “Create Profile”

Then click the “Next” button on the wizard that comes up. You can then give it a name. I used “slack” for my standalone profile.

3. Start Firefox with the Profile

• Select the newly created profile
• Uncheck “Use the selected profile without asking at startup”
• Click “Start Firefox”

After these steps, you can now run the same command as step 1 and get a standalone web app.

Make an Application Shortcut

This step is optional, but makes it easy to launch slack unless you always want to launch it from the command line.

Create a slack.desktop file in ~/.local/share/applications directory with the following content:

#!/usr/bin/env xdg-open
[Desktop Entry]
Version=1.0
Terminal=false
Type=Application
Name=Slack
Exec=firefox --class=Slack -P slack -no-remote https://kash.slack.com
Icon=chrome-jeogkiiogjbmhklcnbgkdcjoioegiknm-Profile_1

For Icon= I just reused what Chrome Apps used. If you don’t have that, I guess just look for a slack icon yourself and put the path to the file in there.

Finally refresh GNOME to get the shortcut to show up by pressing Alt + F2 and then type r as the command.

Hide Toolbars

Lastly, hiding Firefox toolbars to make things really look like a standalone app. Again, this is optional as well, but you probably want it.

Launch Slack standalone Firefox instance, then install the Stylish and the Hide Tab Bar With One Tab addons.

Create a Stylish style with the following content:

@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);

#urlbar-container { display: none !important }
#nav-bar {
  display: none !important;
}

#navigator-toolbox::after {
  display: none !important;
}

That’s it! Standalone Slack with Firefox.