Terms weren't disclosed.
Shares of the San Francisco team-messaging company at last check were 4.4% higher at $32.85.
"Rimeto offers an enterprisewide searchable directory, automatically integrating information from across your company to deliver rich profiles of every employee, their skills, experience, and current projects," Slack said in a statement.
Rimeto’s advanced profile and directory features will be integrated into Slack directly, the statement added, "but we will also continue to offer Rimeto as a stand-alone product and support their existing enterprise customers.”
Founded in 2016 and based in San Francisco, closely held Rimeto is a software-as-a-service company employing about 50, according the company's LinkedIn page.
Last year, the company received $10 million in Series A funding, its first outside investment, from USVP, Bow Capital, Floodgate, and Ray Dalio, founder of Bridgewater Associates, the world's largest hedge fund.
The company said in a statement that "by turning static employee listings into a dynamic enterprisewide view of employees and their activities, companies can now unlock collective knowledge across their organization."
Slack said it is not updating its full-year guidance, which it provided on June 4, since the acquisition is not expected to have a material impact on Slack's results.
Slack recently unveiled the Slack Connect Service, which allows as many as 20 organizations to communicate via Slack’s Shared Channels feature. A larger number of organizations is expected to be supported over time.