Facebook Marketing Partners are currently being offered the opportunity to let clients beta test the new ad units.

Facebook is getting closer to an official Stories Ads launch date. The company is now inviting Facebook Marketing Partners to begin building integrations for the coming ad product and is opening Stories Ads to its clients.

According to social media marketing consultant Matt Navarra, who shared a notice Facebook sent to its Marketing Partner network, Facebook is requesting vendors in its Marketing Partner program ask their clients to run campaigns during this beta period and set Stories Ads as the default opt-in for their ad management platforms.

Facebook began testing the Stories Ads in the US, Mexico and Brazil in May and has since given a limited number of global advertisers access to the new ad unit.

In July, Facebook COO Sheryl Sandberg questioned whether or not Stories Ads would be the revenue driver the company hoped they would be during its second-quarter earnings report. “The question is, will this monetize at the same rate as News Feed? And we honestly don’t know; we’ll have to see what happens. There are good reasons to be very optimistic about the monetization,” she said.

Facebook says Stories on the platform are being viewed by 150 million people. As it readies the ad product for advertisers, the company is also pushing more Page owners to take advantage of the Stories format.

If Facebook wants to sell more ads within Stories, it is going to need more content. In June 2017, Instagram reported more than 250 million of its users viewed Stories. Last month, the company said more than 400 million people are using Stories now — 300 million more than the 150 million viewing Stories on Facebook, which has nearly 1.5 times the audience that Instagram has.

Simon Lejeune, the head of user acquisition for Hopper and a Facebook advertiser with early access to the Stories Ads, told Marketing Land last month that he predicts his company will shift more of its ad budget to new placements like Facebook Stories Ads once they become available.

“There’s something that happens when a new ad placement appears in a feature where it wasn’t present before,” said Lejeune. “Users are more responsive to it because it’s new and they’re not used to the ads or tired [of] them yet.”