Whether we work in cubicles, the C-suite, or a home office, we’re always navigating the people and cultural norms shaping our workday.

As Slack’s founder and CEO, Stewart Butterfield has been the face of the enterprise chat app.

But when the company won an award for fastest rising startup at TechCrunch’s annual tech awards show Feb. 8, it wasn’t Butterfield who took the stage but four black women: Megan Anctil, Erica Baker, Kiné Camara, and Duretti Hirpa.

“We’re engineers,” Camara said to a wave of applause.

In her acceptance speech, she emphasized the importance of diversity in tech companies:

There are many things that are major keys to the success of Slack, not least of which are diversity and inclusion. The idea that diversity of companies improve the culture and bottom line may be somewhat controversial, but all we know is we’ve got 9% of women of color in engineering at Slack, four of whom are up here tonight in formation. And we’re the fastest-growing enterprise software startup of all time, so…

As she trailed off, all four women put their hands out and shrugged. The gesture, as The Root’s Diana Ozemebhoya Eromosele interprets it, was their way of saying: “Tech companies, what’s your excuse for your lack of diversity? We’re diverse and successful. Now what?”

A Slack spokeswoman tells Quartz that Butterfield wasn’t able to make the event and asked the women to accept the award on behalf of the company if it won. ”It seemed appropriate that the award for ‘Fastest Rising Start-up’ should be accepted by the very employees who made it possible,” she said. “With respect to diversity, we can focus on numbers, which are important, but equally important is changing the archetype of what people believe an engineer looks like. The women on that stage are what engineers at Slack look like. Representation matters.”

In September, Slack released data regarding the diversity of its staff. It wasn’t stupendous. But the company made enough progress over the next three months that it issued an update in February. Of its engineering staff globally, 7.8% are black, up from 7% previously. The engineering team—typically the least diverse department both in terms of gender and ethnicity at many tech companies—is now a quarter female, up from 18% in September.