This page contains a list of open library communities on Slack.
Even though code4lib has its own website with IRC and a wiki, much daily conversation takes place in its Slack site. code4lib has over 500 users and 24 channels including the code4lib IRC channel.
Datalibrarians of Florida
As you can tell by the name, this Slack community is aimed at technical librarians in Florida.
The LibApps Slack site was started recently as an alternative to the official Springshare Lounge. It has over 150 members and 16 channels covering all Springshare apps and more.
The LibTech Slack site is less technical than code4lib and broader than LibUX, covering all library technology topics. If you want to learn what Slack is about, come join this group as a founding member. Help us reach critical mass and suggest some appropriate channels.
The LibUX site is perhaps the most active of the library Slack communities with over 200 members discussing library user experience topics in 13 channels.