Slack Picks Up $250 Million in Funds from SoftBank

Chances are, iPhone app developers have used Slack or are currently using it to ease communication and collaboration in their work lives. It’s a valuable tool, and it has been steadily improving recently. A few weeks ago, the startup aped a feature from competitor (and one-time potential acquirer) Microsoft that gives companies the ability to set up channels that guests from other organizations can join. This kind of feature is a crucial addition to a tool that needs to be adopted by huge multinational corporations if it wants to continue to grow and thrive.

There has been some ambiguity about whether or not Slack has legs outside of Silicon Valley, where it has been championed as the workplace tool of the future and a smart investment. It faces some nasty competition, including Microsoft’s beefed-up Skype and Atlassian’s Stride, which was launched earlier this month. But the startup continues to flourish in ways that silence the doubters. According to the latest numbers from Slack, the tool can claim $200 million in annual recurring revenue and 6 million active users a day. San Diego iPhone app developers know those numbers are nothing to sneeze at. There’s a reason Amazon and Microsoft have both considered dropping billions to acquire the company.

But for now, Slack is doing quite well on its own. Hot off of investments in everything from Chinese online insurance to Indian hotel-booking startups, SoftBank Vision Fund, the world’s largest private equity fund, just gave Slack $250 million. This injection of funds brings the startup’s valuation to a stunning $5.1 billion. The gossip back in July, when Amazon was sniffing around, was that Slack wanted to pick up $500 million in funding. SoftBank’s faith and generosity only went half that far, but maybe that’s enough. Slack founder and CEO Stewart Butterfield said in a statement today, “We believe that Slack is the future of work, and this fund reinforces that – providing long-term operational flexibility and resources that prepare us to run Slack as a cash-generating company and move quickly as the market evolves.” iPhone app developers will be watching closely as Slack continues this evolution.