Unicorns 34/229 – Slack

Unicorns 34/229 – Slack


Founders: Stewart Butterfield, Eric Costello, Cal Henderson, Serguei Mourachov
Key people: Stewart Butterfield (CEO)
Number of employees: ~700 (Q4 2016)

Slack Technologies, Inc. (originally Tiny Speck) is a Canadian software company founded in 2009 in Vancouver, British Columbia, Canada. The core team is largely drawn from the founders of Ludicorp, the company that created Flickr. Slack is the fastest company to receive a billion dollar valuation. Outside its headquarters in San Francisco, California, Slack operates offices in Dublin, Vancouver and Toronto.


Slack was launched in August 2013. In January 2015, Slack announced the acquisition of Screenhero.

In March 2015, Slack announced that it was hacked over the course of four days in February 2015, and that some number of users’ data was compromised. That data includ ed email addresses, usernames, encrypted passwords, and, in some cases, phone numbers and Skype IDs that users had associated with their accounts. In response, Slack added two-factor authentication to their service.