Slack Raises $160M at $2.8B Valuation

Slack's Offices
Slack Co-Founder and CEO Stewart Butterfield
Slack on Mobile

Daily active users more than doubled since beginning of year.

Slack, the essential team communication platform, today announced it has raised $160 million in new investment at a post-funding valuation of $2.8 billion. New investors include Horizons Ventures, Digital Sky Technologies (DST Global), Index Ventures, Spark Capital Growth, and Institutional Venture Partners (IVP). All existing investors participated in the round. Slack previously raised a total of $180M from Accel Partners, Andreessen Horowitz, The Social+Capital Partnership, Google Ventures, and Kleiner Perkins Caufield & Byers (KPCB).

Slack continues its trajectory as the fastest growing business app ever. Having launched in February 2014, Slack is now used daily by over 750,000 people, and has over 200,000 paid seats. Both daily active users and paid seats have more than doubled since the beginning of the year.

Slack’s traction demonstrates an appetite for a new set of tools that reflect the evolution of technology and the nature of work. People love it because it has an immediate and fundamental impact on their work lives. Some of the customers benefiting from the radically improved transparency and efficiency across its teams thanks to Slack include: Adobe, New York Times, Blue Bottle Coffee, BuzzFeed, Live Nation, Expedia, HBO, and PayPal.

“We take a very long view of both the opportunity before us and the company we want to build. We’re still at the beginning of a major transition in how people communicate and work together,” said Stewart Butterfield, CEO of Slack. “Our new roster of investors reflects Slack’s global audience, and they’ll be essential partners in our continued growth.”

“Stewart and the team at Slack have taken a page out of the consumer playbook and revolutionized business communications by taking a generationally-different approach to messaging,” said Mike Volpi, partner at Index Ventures, who as part of the investment, has joined Slack’s board of directors as an observer. “Slack has reached a level of early traction that's rarely seen on the enterprise side, and we're incredibly excited to support their continued growth.”

The current board of directors consists of CEO Stewart Butterfield, Andrew Braccia (Accel), John O’Farrell (Andreessen Horowitz), and Mamoon Hamid (Social+Capital). John Doerr (KPCB) and M.G. Siegler (Google Ventures) were named as observers in the last investment round.

To sign up for Slack, find out more about job opportunities, and keep up on the latest news, visit and follow @slackhq.

About Slack

Slack is a messaging platform for teams which brings all communication together, creating a single unified archive accessible through powerful search. It integrates with dozens of popular services such as Twitter, Dropbox, Trello, Asana, Google Docs, JIRA, MailChimp, Stripe, Zendesk, and others to help consolidate and make sense of the ever-growing flows of data that confront modern teams. Based in San Francisco, and with offices in Vancouver, Slack has raised $340 million from some of the world’s best recognized investors including Accel, Andreessen Horowitz, Social+Capital, KPCB, Google Ventures, Horizons Ventures, IVP, Spark, DST, and Index.

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Published — April 16, 2015