Slack is a cloud-based set of proprietary team collaboration tools and services. It began as an internal tool used by his company, Tiny Speck, in the development of Glitch, a now defunct online game.

Slack is where the right people are always kept in the loop and key information is always at their fingertips. Work in Slack happens in channels, so all the right people can be included, all relevant information kept in one place, and new team members are able to get up to speed easily. With Slack, teams are better connected.  

Slack was founded in 2009 in Vancouver, British Columbia, Canada by Stewart Butterfield & Cal Henderson. The company is headquartered in San Francisco, California with offices in NY, Vancouver, London, Toronto, Dublin, Melbourne & Tokyo. 

Slack brings team communication and collaboration into one place so you can get more work done, whether you belong to a large enterprise or a small business. 

Slack integrates with a large number of third-party services and supports community-built integrations. Major integrations include services such as Google Drive, Trello, Dropbox, Box, Heroku, IBM Bluemix, Crashlytics, GitHub, Runscope, Zendesk, and Zapier.


Slack is one of the fastest growing startup, winning many awards including "Best Startup of the year at the Crunchies in 2017.


Slack was valued a whopping $7.1B at their "Series E" funding on Aug 21, 2018, where they cashed $427M. They are backed by top venture firms including Accel, Kleiner Perkins, SV Angel, Andreessen Horowitz, and GV among others. Slack has acquired 6 other companies to date including Spaces, HipChat, Stride and Astro Technology among others. They have also made over 20 investments to date.


Slack went public on June 20, 2019 with IPO valuation of over $20B.



  • Year founded: 2009
  • Funding Info: $1.2B in 11 funding rounds (Last funding type: Series H)
  • Yearly Revenue: $200M-$300M (2018)
  • Employee Size: 1000-5000
  • Business Valuation: Valued $7.1B as of Aug 21, 2018/ IPO Valuation: $20B+ as of June 20, 2019
  • City/Town: San Francisco
  • State: California
  • Country: United States
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