Facebook is bringing bidding to in-app ads, the company is expected to announce on Wednesday. Now, members of Facebook’s Audience Network can bid into auctions for publishers that manage app monetization in house.

For publishers managing app monetization externally, Facebook is partnering with MoPub, Fyber and MAX. For Facebook, the changes are part of a broader effort to offers brands more advertising options.

“App bidding provides publishers with opportunities to earn more from advertising,” a Facebook spokeswoman said. “Bidding enables publishers to conduct a real-time auction between ad networks to determine which one gets to serve an advertisement to a person using their app.”

“The ad network willing to pay the most for the impressions gets to serve the ad, as opposed to today’s current waterfall system, based on historical CPMs,” she added.

Last March, Facebook announced Audience Network support for mobile Web header bidding.

With header bidding, publishers can conduct real-time auctions between ad networks to determine which one gets to serve an ad to users browsing a mobile website.

In recent months, Facebook has been testing its app bidding endpoint with several publishers that monetize their apps using their own ad server technology. In these tests, publishers have seen revenue lift of up to 20%, according to Facebook. Industrywide, header-bidding technology for app inventory continues to show significant growth, research  suggests.

For PubMatic, global app impression volumes rose 84% from the first quarter of 2017 through the same period in 2018. That outpaced the 28% growth rate for mobile web inventory over the same period, according to the publisher-focused sell-side platform.