Microsoft Teams-Slack calling integration is coming, says Slack CEO

Slack may be adding yet another Microsoft integration to its platform. But this time, it might be an integration with archrival Microsoft Teams.
Written by Mary Jo Foley, Senior Contributing Editor
Credit: Slack

The Slack group-collaboration platform already is integrated with a number of Microsoft Office services, including Outlook, OneDrive and SharePoint. But it soon may be integrated with Microsoft Teams' calling capabilities, according to Slack CEO Stewart Butterfield.

Butterfield announced the coming integration during a call with RBC Capital Markets on March 26, according to CNBC, which reported the news. He didn't provide a timeframe as to when it would be available, CNBC noted.

Like Teams, Slack has built-in voice and video calling as part of its platform. Slack already has the ability to start voice or video calls from within Slack using the command /skype .

I asked Microsoft if the company was working together with Slack on this type of calling integration and/or whether Slack was doing this using publicly available programming interfaces. A Microsoft spokesperson said the company had "nothing further to share at the moment." I asked Slack the same question but didn't hear back. 

Updated (March 27): A Slack spokesperson said Slack will be delivering this integration using publicly available APIs.

Update 2 (March 30): A Microsoft spokesperson provided a statement (indirectly) echoing what Slack's spokesperson said. "Our Microsoft 365 application programming interfaces (APIs) are public and open to customers and all third party developers. Providing developers with access to our services enable ISVs to tap into and extend the powerful capabilities of Office and Microsoft Teams."

During its fourth quarter FY20 earnings, Slack officials said that the "majority" of Sack's $1 million and above customers also use Microsoft's Office 365, the commercial versions of which includes Teams for no additional cost.

Microsoft recently disclosed that Teams currently has 44 million daily active users. Slack officials have declined to say how many daily active users Slack currently has; the last figure it shared publicly in October 2019 was 12 million.

Editorial standards