Slack confirmed Friday that it had raised $200 million in a round led by Thrive Capital with funding from venture capital firms including GGV Capital, Comcast Ventures, Accel Partners, Social Capital, Spark Growth and Index Ventures.
The latest round brings the workplace messaging company's valuation to $3.6 billion according to The New York Times. Slack was valued a year ago at $2.8 billion, when it last raised funding. The company has now raised a total of $540 million.
"As has always been the case, we are taking this opportunity to further secure our leadership position as we continue to execute on our ambitious growth plans. This capital adds to our existing reserves and increases our ability to focus on an uncompromising long-term, strategic view," CEO Stewart Butterfield said.
The company says it has 430 employees and the service serves 2.7 million daily active users and 800,000 paid users.
Despite the rosy picture painted by the large round and climbing valuation, the Times notes that critics warn of Slack potentially facing future growth issues. While popular with tech companies and startups, larger corporations may be hesitant to get on board. Uber recently dropped Slack because it could not handle the volume of employees trying to communicate at once.