Slack passes 500K daily users and 135K paying customers in time for its first birthday

Billion-dollar team messaging app Slack celebrated its first birthday today.

While promoting the milestone, the one-year-old revealed that it now has 500,000 daily active users, 135,000 paid accounts, and $12 million in annual recurring revenue.

The Silicon Valley darling officially launched to the world on February 12, 2014, but it reportedly did so with 16,000 daily active users already onboard — that’s because Slack debuted in private beta nearly six months earlier. If you count its private beta period, Slack launched in August 2013, when it managed to sign up 8,000 companies in 24 hours.

One year since launching out of private beta, Slack tells us “60,000 teams” of various sizes now actively use the service. Across its mobile, web, and desktop apps, Slack claims its service is quite sticky: “On average, Slack’s users spend 2 hours and 15 minutes each weekday in active use … and 9 hours and 23 minutes connected to the service,” the company said in a statement.

In October, Slack said it would be “the fastest-ever SaaS company to reach $10 million” in annual recurring revenue. Today, the company calls its rate of adoption “unprecedented,” while Redpoint Ventures partner Tomasz Tunguz claims it’s the “fastest growing B2B company to hit [the above] milestones in 12 months.”

That’s a familiar refrain for Slack: record growth.