Facebook plans a free version of its Slack competitor

Facebook CEO Mark Zuckerberg speaks during an event at Facebook headquarters.

Justin Sullivan | Getty Images

Facebook is introducing a free version of Workplace, its social networking tool for workers to chat and collaborate.

"We're making Workplace work for more companies, so it's a pretty big step for us," Facebook product manager Simon Cross told CNBC.

The new product — which is still being tested and so not widely available — will look and feel the same to users as the paid version, but it's self-serve and will not offer companies the administrative and analytical tools available to paying subscribers.

Workplace is similar to regular Facebook, but instead of connecting with friends and family, its users interact with co-workers.

It will be called "Workplace Standard," while the paid version will be called "Workplace Premium."

"Not every company wants to go through a full-scale enterprise deployment and not every company is in a position to pay for Workplace," Cross said.

Customers wanted an easier way to sign up for Workplace and a version of the product that worked for smaller companies, across different verticals, in different parts of the world, said Cross.

The social networking giant is betting that a free version will entice small businesses and companies in emerging markets — often more cost-sensitive — onto the platform.

"We hope it helps grow the number of companies that we're able to connect," he said.

"They can use it in their team, they can use it in their department and maybe eventually go on to deploy Workplace Premium across the company, but with Workplace Standard they can get started for free," he added.

Facebook faces dozens of rivals, all chipping away at the dreaded email inbox.

They include Microsoft which introduced workplace chat tool Teams in November and is working to integrate LinkedIn into its products and services, and start-up Slack, which has 5 million daily active users and 1.5 million paying subscribers.

Facebook has signed up "thousands" of paying subscribers to Workplace Premium, which officially launched in October, spokeswoman Vanessa Chan told CNBC.