Ad mediation

What is Ad mediation?

Ad mediation is a technology layer that connects mobile app publishers to multiple ad networks through a single SDK integration, enabling automated selection of the highest-value ad to fill each available impression. Publishers use ad mediation platforms to manage and optimize demand from multiple sources simultaneously, rather than integrating with each ad network individually. The result is a more competitive auction environment, higher fill rates, and improved ad revenue.

How it works

Ad mediation platforms are integrated into mobile apps via an SDK before launch. When an ad impression becomes available, the mediation platform receives a bid request and coordinates demand sources to compete for the impression. The platform then selects the winning ad and delivers it to the user. Two primary techniques govern how this process works.

Waterfall Bidding

Waterfall bidding is the traditional mediation method. Publishers rank their preferred ad networks in a prioritized list. When an impression is available, the mediation platform works down the list sequentially, requesting a bid from each network one at a time. If the top-ranked network does not fulfill the request at an acceptable price, the request passes to the next network, and so on. The first network to meet the minimum acceptable bid wins the impression. Networks ranked lower in the waterfall are never given the opportunity to bid once a qualifying offer is accepted, even if they could have offered a higher price. This structure gives publishers predictability and control over their demand partners but can leave revenue on the table by not exposing every impression to the full range of competition.

In-App Header Bidding

In-app header bidding, also called in-app bidding, addresses the limitations of the waterfall model. Instead of sequential requests, all connected ad networks and demand sources bid simultaneously for a single impression using real-time bidding technology. Every demand source competes on equal footing, with no predefined order. The highest bid wins the impression automatically. This parallel auction approach increases competition, reduces latency compared to waterfall chains, and consistently surfaces the true market price for each impression.

Why it matters

Ad mediation is a foundational tool for mobile app monetization. Publishers managing ad revenue without mediation must integrate and manage each ad network separately, which is operationally burdensome and limits the competitive pressure that drives higher CPMs. Mediation platforms consolidate this complexity into a single integration point, allowing publishers to work with a broader set of demand partners without multiplying their SDK overhead.

Higher fill rates follow directly from broader demand access. When more networks compete for each impression, the likelihood of filling that impression at an acceptable price increases meaningfully. At the same time, greater competition among bidders pushes CPMs upward, improving the revenue generated per thousand impressions.

For publishers operating at scale, the difference between a well-configured mediation stack and a poorly managed one is significant in terms of effective CPM and overall monetization performance. Choosing between waterfall and in-app header bidding, or a hybrid of both, has a direct impact on how efficiently inventory is monetized. MMPs like Airbridge work alongside mediation platforms by providing attribution and campaign analytics that help publishers and advertisers understand which demand sources drive the most valuable users, enabling more informed decisions about network prioritization and budget allocation.

How to implement ad mediation for mobile apps

1. Select a mediation platform. Evaluate platforms based on the ad networks they support, SDK weight, reporting capabilities, and compatibility with your app's category and audience. Major platforms include Google AdMob, ironSource, AppLovin MAX, and Unity LevelPlay.

2. Integrate the mediation SDK. Add the mediation platform's SDK to your app before launch, following the platform's technical documentation. This single SDK replaces the need for individual network integrations.

3. Connect your ad network accounts. Link each ad network you want to monetize through the mediation dashboard. Provide the necessary API keys or account credentials for each network.

4. Configure your waterfall or in-app bidding setup. For waterfall setups, rank networks based on historical eCPM data and business relationships. For in-app bidding, ensure all participating networks support the real-time bidding protocol used by your mediation platform.

5. Set floor prices. Define minimum acceptable CPMs to ensure impressions are never filled below a threshold that is unprofitable. Adjust floor prices based on geography, placement type, and ad format.

6. Test ad placements. Use test mode in the mediation SDK to verify that ad formats display correctly across devices and that impression tracking fires accurately.

7. Monitor performance and optimize. Review fill rate, eCPM, and revenue per network regularly. Adjust waterfall rankings or floor prices in response to performance data. Connect your mediation data with an MMP like Airbridge to cross-reference ad revenue with user acquisition costs and lifetime value, ensuring your monetization strategy aligns with overall growth goals.

8. Iterate with A/B testing. Many mediation platforms offer built-in A/B testing for waterfall configurations or floor prices. Use these tools to test changes before rolling them out broadly.

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