Slack, which makes software to help improve team communication, said it raised $160 million in a round of funding, valuing it at $2.8 billion.
The San Francisco-based startup, whose tool helps people exchange messages, videos and images, said new investors include Horizons Ventures, Digital Sky Technologies (DST Global), Index Ventures, Spark Capital Growth, and Institutional Venture Partners.
Slack, which also integrates services such as Twitter , Dropbox and Google Drive into its application, had all its investors participating in the round, the company said in a release.
The application, which was launched in February 2014, is used daily by over 750,000 people, and has over 200,000 paid seats, the company said.
Slack said its daily active users and paid seats have more than doubled since the beginning of the year.
Slack had earlier raised a total of $180 million from Accel Partners, Andreessen Horowitz, The Social+Capital Partnership, Google Ventures, and Kleiner Perkins Caufield & Byers.
