Ad mediation is the orchestration layer between a publisher's ad slots and the multiple ad networks / demand sources that fill them. Without mediation, a publisher integrates one ad network and accepts whatever fill rate and eCPM that network delivers. With mediation, the same publisher integrates 5-15 demand sources and routes each impression to the source most likely to pay the most for it. The eCPM lift is substantial — typically 30-100% vs single-network — which is why every serious mobile-app publisher runs mediation.
Evolution of mediation logic
- Classic waterfall (2010s): networks called in fixed priority order. Highest historical-eCPM network first; if fill fails or bid below floor, fall through to the next network; continue until something fills. Simple but leaves money on the table.
- Header bidding / unified auction (late 2010s onward): all demand sources bid simultaneously in real-time, highest bid wins. Lifts eCPM 10-30% vs waterfall but requires more complex integration.
- Hybrid stacks (2026 norm): combination of bidding-enabled networks running unified auctions PLUS waterfall-only networks running after the auction for fall-through fill. Maximum coverage.
Major mediation platforms in 2026
- AppLovin MAX — market leader. Strongest unified auction implementation, broadest demand source integration, mature analytics.
- ironSource LevelPlay (Unity LevelPlay) — strong runner-up. Gaming-heavy demand strength, deep Unity integration.
- Google Admob Bidding — Google's mediation product with bidding. Best for publishers already in the Google ecosystem.
- Liftoff Vungle — mobile-focused mediation with bidding.
- Smaato / Verve — mobile-app-focused with bidding.
Most large publishers use one primary platform with secondary integrations for risk management.
What ad mediation orchestrates
- Demand sources — SAN networks (Meta Audience Network, Google AdMob, AppLovin), SSP integrations (Magnite, PubMatic, OpenX), in-app exchanges (AppLovin Exchange, ironSource Exchange).
- Auction logic — unified real-time auction across bidding-enabled sources, fall-through waterfall for non-bidding sources.
- Floor price management — minimum eCPM thresholds, often configured per geography / format / time-of-day.
- Frequency capping — max impressions per user per ad-network or per advertiser.
- Brand safety — blocklisted advertiser categories applied across all networks.
- A/B testing — testing floor prices, network priorities, ad formats, placement strategies.
- Reporting — unified eCPM / fill / revenue reporting across all networks.
Choosing a mediation platform
- AppLovin MAX: usually the right default for mobile-app publishers in 2026. Most demand sources, mature analytics, strong unified auction.
- ironSource LevelPlay: strong alternative if you're gaming-heavy or already on Unity. Tight Unity Editor integration.
- Google Admob: best if you're a smaller publisher or already deep in the Google ecosystem. Simpler onboarding, but less competitive demand for non-Google networks.
- Multiple in parallel: rarely worth it. Pick one as primary, layer secondary integrations only for specific networks unavailable through your primary.
Switching is painful. SDK is deeply embedded; historical eCPM data lives in the platform; demand partner contracts route through it. Most publishers stay with one mediation platform for 2+ years even when frustrated.