Slack cofounder Cal Henderson says having Microsoft become your top competitor is like when "you slowly boil a frog"

Slack

Slack CTO and cofounder Cal Henderson

• Workplace messaging app Slack was only founded nine years ago, but it has exploded in popularity to become a $7 billion company that Microsoft sees as a threat.
• As Slack grows, Microsoft has been trying to up its own office messaging game with Microsoft Teams.
• "The whole experience over the last few years has been like when you slowly boil a frog," Slack CTO and cofounder Cal Henderson.

Slack, a $7 billion workplace messaging company founded nine years ago, now has the trillion-dollar Microsoft as its biggest competitor. And it's not a one-way street -- Microsoft sees Slack as a threat.

This didn't happen overnight, Slack CTO and cofounder Cal Henderson said Monday at Business Insider's Ignition conference in New York.

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"The whole experience over the last few years has been like when you slowly boil a frog," Henderson said onstage. "They don't realize the water is getting hotter and hotter."

In August, Slack raised a massive $427 million to become a $7.1 billion company, and it's not backing down. Meanwhile, Microsoft has been working to promote its own office messaging product, Microsoft Teams.

Still, having Microsoft as a competitor can be a good thing for Slack.

"It's huge validation when a huge competitor like Microsoft enters the same space and builds a similar product," Henderson said. "They're saying, this is a product space that will continue and be important and enter into the next decade."

Since Slack started in 2009, the company has grown immensely. The first year and a half of the business was just building the product, and Henderson says his role has changed immensely from then to now.

Once you're sick of saying it, people start listening

"Once you build a product that fills the need that people need, then you can turn it into a business," Henderson said. "...My role as a leader largely becomes one of delivering priorities and vision. Once you're really sick of saying that, that's when people really start to hear it."

The key, Henderson says, is to believe that "you're definitely going to be successful."

"You have to believe this, even in the case of evidence like, all the odds are against you, but this time around, you're definitely going to be successful," Henderson said.

Read more: Microsoft is acquiring a Texas-based AI startup as it prepares for the next wave of the cloud wars

Now that companies like Slack, Microsoft and Google are vying for the top spot in office messaging, it shows how enterprises are increasingly working to increase communication. While these apps can increase teamwork, Henderson emphasizes, it won't completely replace in-person communication.

"Face-to-face communication is still so rich," Henderson said. "That's never going to replaced by technology and media. We still get together when we can."

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