Slack workspace name checker
Slack doesn't have public usernames; what's unique is the workspace address, yourname.slack.com. This checker tells you whether that address is already in use before you create a workspace or rename one.
Workspace URLs are 3 to 21 characters using letters, numbers and hyphens. An existing workspace shows a sign-in page, and a free address returns an error page, which is exactly what we look for.
If you're launching a community, a course or an open-source project, check the same name as a domain and across social platforms so members find the right place everywhere.