Why Unity is moving to 100% in-app bidding
2024 marked the start of a new era as in-app bidding took over mobile ad monetization, replacing decades-old “waterfall” mediation methods. Unity Ads, ironSource Ads, and LevelPlay joined the bidding revolution with a global, cross-functional team effort.
As a result, advertisers gained more impressions, publishers streamlined operations, and gamers enjoyed better experiences with faster load times. Here’s why the shift to bidding matters for publishers and networks and what’s next in 2025 for Unity Ads and ironSource Ads bidding.
How in-app bidding helps publishers
In-app bidding is a common-sense concept: let every network compete, let the highest bid win, and pay exactly that amount to the publisher. Yet for more than a decade, the industry stuck to the “waterfall” auction concept, in which prices start high and gradually lower until someone bids. Imagine starting at $100 and opening the auction to only the top three networks, if none of them agree to the price it then drops to $50 and a few more networks are added. This repeats up to a hundred times per ad impression. It’s time consuming, complex, and opaque.
In-app bidding streamlines the process of finding the best price for each impression with a first price auction that resolves in seconds rather than minutes.
In-app bidding enables ad networks to continue to benefit from the SDK while conducting auctions server-side. Here’s how it works:
- First, to authenticate the request as non-fraudulent, meditation requests a ‘token’ from each network SDK client-side.
- Each bidder is called in parallel by a server with strict timeouts to return a bid, along with the content they’d like to show if they win. After the winning bid is chosen in auction, the winners and losers are notified.
- Mediation loads the winning network’s ad into its SDK, ready to show to the user.
Overall, processing is reduced and publishers get real-time transparency into each user’s true value. Networks can freely compete based on their best offers, ensuring publishers always get fair market value for premium users. As a result, publishers spend less time micromanaging complex auctions and more ad networks get a shot at winning, leading to increased competition and higher CPMs for publishers.
How in-app bidding helps Unity ad networks
The benefits of in-app bidding aren't just for publishers. The Unity Ads and ironSource Ads networks have achieved significant improvements to the scale of app installs with in-app bidding. This is primarily for two reasons:
- Unity Ads and IronSource Ads networks get access to win all users on a level playing field. Before bidding, the publisher could set a limited number of price points in the auction and these could often be inconsistent across formats, geos, and even networks. Sometimes publishers would prioritize one network over others.
- Bidding improves the efficiency of the tech stack for machine learning. A more efficient ad serving process delivers cleaner data at lower cost to Unity’s models, which in turn enables today's increasingly complex, deep-learning models to deliver more accurate real-time decisions. This cycle helps Unity to drive advertiser performance, which lifts publisher performance with it.
The move to in-app bidding and what’s next
In 2024, Unity Ads completed the re-write of its entire ad serving stack to unlock the full potential of bidding for publishers. In conjunction, Unity LevelPlay mediation and ironSource Ads also made great strides towards 100% bidding. This required working with publishers and other top networks, collaborating effectively to drive growth for the industry at large.
Unity Ads plans to move to 100% bidding in 2025, beginning with 100% bidding in some external mediations and an open Beta for Google AdMob and Ad Manager, now live as of February 4th. This will be followed by the retirement of the waterfall and the introduction of the v5 SDK architecture optimized for bidding.
LevelPlay mediation will continue to integrate new bidding ad networks and complete the roll-out of multiple ad units. Levelplay will retain legacy support for waterfall integrations while working with publishers and networks to migrate to bidding.
Overall, with access to the best supply and data for machine learning, in-app bidding positions the entire mobile ecosystem for growth through efficiency in 2025.