The retail giant said Tuesday that it is now a customer of Facebook Workplace, essentially a business version of the social network.

Facebook debuted Workplace last year as a work-productivity tool that easily connects to employees’ existing Facebook accounts. But unlike the traditional version of Facebook, companies must pay to use Workplace.

“Walmart’s vision of the future is centered around people–by serving the communities people live in and the people who work at Walmart,” Walmart chief information officer Clay Johnson said in a statement. “Workplace shares this mission, and together we’re building the next generation workforce.”

Having a major company like Walmart as a customer is a major PR coup for Facebook, which is hoping to diversify from online ad revenue. In a blog post on Tuesday, Facebook said that over 14,000 companies now use the Workplace software, the same number the social networking company revealed in April during its annual developer conference—signaling that Facebook may be having trouble adding new corporate customers.

The workplace software market has become a tough battleground for many tech companies including Facebook (FB), Microsoft (MSFT), Cisco (CSCO), Google (GOOG), and the business software companies Slack and Atlassian (TEAM). All of these companies sell competing workplace software that place a heavy emphasis on employees chatting and collaborate with one another.

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Earlier this week, Microsoft said it plans to phase out its Skype for Business online phone service in favor of its newer Teams app, which is built around chatting and document sharing.