The four-year old startup challenger to Microsoft and Google raises $472m from investors in latest fundraising round.
Slack has raised $472m in its latest funding round, valuing the popular business messaging app at more than $7.1bn (£5.6bn).
The San Francisco-based company, which was valued at $5.1bn almost a year ago, has raised more than $1.26bn since its launch in 2014.
By raising the money from existing shareholders and new investors, the startup avoids the scrutiny of seeking a stock market listing. It had a recurring revenue of $200m last year.
Slack is challenging Microsoft and Google to replace email and messaging apps allowing employees the ability to collaborate on projects and documents. It also allows companies the ability to integrate their own software.
“We pursued this additional investment to give us even more resources and flexibility to better serve our customers, evolve our business, and take advantage of the massive opportunity in front of us,” the company said.
“Even with our rapid growth in just four years-we now have more than 8 million Daily Active Users (DAUs) and more than 70,000 paid teams-there is still enormous potential to change the way that people and organizations collaborate and work together.”
While the product is free, Slack has three million paying subscribers, including IBM, CNBC and eBay.