YC leads $50M Series B in Mattermost as open source Slack alternative
Today, we’re delighted to announce that Y Combinator Continuity is leading a $50M Series B investment in Mattermost as an open source alternative to Slack and Microsoft Teams. With today’s announcement, Mattermost becomes YC’s largest ever Series B investment, and more importantly, their largest open source investment to date. YC is joined by our existing investors, Redpoint and S28 Capital, and new investor Battery Ventures.