Slack’s CEO Stewart Butterfield has revealed the comms platform is working on a call integration with its fierce rival Microsoft Teams.

The plan was announced during an investor webcast with RBC analyst Alex Zukin on Thursday.

Butterfield’s view is that the number of users for both services will dramatically grow over the next five years and it’s pointless fighting over what they have now. Teams has the edge currently, largely due to it coming bundled into Office 365, but Slack has become a popular choice for companies that use multiple cloud-based communication platforms.

The two companies have recently reported spikes in daily active users during the current COVID-19 pandemic, with Teams reporting 12 million more since the start of March.

“There are a lot of people who use both, and we’re working on a Teams integration for calling features,” Butterfield said. “I’m pretty sure that in 18 to 24 months time when we look back, that more people use Teams is not going to be relevant to us as a company.”

“95% of people who are going to be using this stuff five years from now have not started, so there is no point fighting over the relatively small percentage of customers we have.”

Slack has often been used in tandem with other services, particularly video calling software such as Google Hangouts and Zoom. Recently, Microsoft singled Zoom out as a potential business threat because of this.

However, Butterfield’s comments suggest a less feisty competition from the two companies. Since Teams was launched the two have traded blows over user numbers, features and even marketing strategies.

In November, Slack accused Microsoft of copying its Adverts, referring to the company as a “boomer”. A few months prior, Microsoft banned its employee from using Slack, suggesting it was “not secure”.