YC leads $50M Series B in Mattermost as open source Slack alternative

“Yet another team workspace / Slack competitor.  Things are getting interesting …”

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.

An open source software company, Mattermost has flourished in high security, privacy-conscious enterprises seeking to increase productivity and empower technical teams through workplace messaging. We plan to use this new funding to accelerate community expansion and product development in a new and fast-growing market. […]