Slack exploded as one of the hottest Bay Area start-ups with a super-simple messaging service that helps teams and small companies cut down on email.

On Tuesday, the company introduced a product called Slack Enterprise Grid designed for larger and more complex businesses. The deal will help the start-up justify its $3.8 billion valuation and fend off competition from the likes of Microsoft.

Some of those big customers include IBM and Capital One Financial. Both the product and new clients were announced at an event in San Francisco.



"These organizations need a different set of tools to help people communicate within and across business lines, and reduce friction around getting work done when multiple groups inside the company are involved," Slack said in an email.

The service includes identity management technology, data loss prevention and advanced security systems, and Slack has gained compliance for use in health care and finance, where strict regulations make it more challenging to digitally move data. The company also said it now has 1.5 million paying users.

In November, Microsoft unveiled a product called Teams, bringing together chat and easier collaboration within the Office 365 cloud suite. Slack welcomed Microsoft to the market with a full-page ad in The New York Times:



Dear Microsoft