The popularity of Slack’s office messaging software in offices around the world means the startup is beginning to attract much bigger competitors.

Compared to the 85 million Microsoft users who receives Microsoft Teams, a Slack-like alternative, as part of its Office 365 package, Slack is still small with 5 million users. Slack doesn’t have the reach or financial muscle of the office software giant, but it does have at its disposal a weapon deployed by underdog companies everywhere—superior customer service.

Slack prides itself on its responsiveness. All of the company’s executive field customer support calls, including CEO Stewart Butterfield, and the average turnaround time for a query is less than an hour, according to the New York Times (paywall). “I get worried if I see customer satisfaction scores dip below 97%,” said Ali Rayl, Slack’s head of customer experience.

Under CEO Satya Nadella, Microsoft has made strides in being more agile and customer friendly, but it’s still a gargantuan company and trying to resolve problems can be a hair-pulling, forehead-on-desk-bashing exercise in frustration. Slack feels it can take advantage of this disconnect—at the heart of Slack’s business case is its claim the product is designed around the needs of its users. “We’re trying to build empathy at scale,” Butterfield says.

That kind of approach is rare: in our increasingly automated, bot-obsessed world, relying on humans to provide customer service is becoming archaic. One of the first large-scale applications of speech-recognition software has been the elimination of customer-support call centers.

But as Slack’s software grows in popularity, and its adoption becomes more widespread, an all-hands-on-deck approach to customer service will become unfeasible and the company will have to decide if it can afford to have humans field calls. How Slack competes with Microsoft without taking on the traits of Microsoft may determine how much longer it can distinguish itself as a product.