Stewart Butterfield’s Slack Raised $43M Million In New Funding

Slack, a collaboration platform founded by Flickr co-founder Stewart Butterfield, is raising $30 million-plus in new funding, we’ve learned. (Update: the company confirmed the day after we published our scoop that it the final amount was $42.75 million).

For background, Butterfield left Yahoo and started TinySpeck (and a multiplayer game called Glitch) but then decided to take a different turn, tackling the enterprise market. Thus Slack was born as a collaboration platform that lets users port in conversations and links to other work from dozens of other apps (including Dropbox, Google Docs, GitHub and Asana). The aim is to track progress on different projects in one platform; reducing email overload.

Over the past few months, Slack has been growing fast, quickly becoming the rising new star in the enterprise collaboration market. The company had said earlier this year that it had plenty of cash leftover from the Glitch days and was heading towards profitability. In the current market it makes sense for the company to raise as growth is ramping up.

In terms of the product itself, we’ve found Slack particularly useful for mobile interactions in teams, and the app lacks the kind of annoying bugs that we’ve all found in its predecessors. And that Slack is growing is a testament to the fact that there is something lacking in the competition. But still, it lacks threaded integrations, which prevents our team from using it.

TinySpeck had previously raised $17 million from Andreessen Horowitz, Accel Partners, Rob Solomon, SV Angel, Jeff Weiner and Bradley Horowitz.

It also wouldn’t be surprising if the company has been the target of some acquisition interest.

We’ve reached out to Slack for comment.