In-House Mediation with Client-to-Server Bidding

Facebook Audience Network Bidding Kit 2.0 is a lightweight SDK that makes it easier for publishers to transition from the waterfall paradigm to in-house bidding. It is intended for in-house publishers that are using a homegrown mediation system, as opposed to publishers that are using hosted advertising solutions such as AdMob, MoPub, or Fyber. Bidding Kit 2.0 helps you implement auctions, integrate with multiple real-time bidders, and customize auctions to meet your needs.

Bidding Kit 2.0 consists of the following components:

  • First-price auctions in which every bidder gets a fair chance to win impressions
  • Adapters that connect to bidding endpoints from a wide range of companies
  • A/B testing that lets you measure the incremental benefits of bidding
  • Well-defined interfaces between auctions and traditional waterfalls


Bidding Kit 2.0 runs auctions and acts as a bridge to current mediation systems. It relies on the publisher's app to load and display ads, in contrast to mediation solutions such as MoPub and AdMob that handle this logic. Bidding Kit 2.0 also integrates with certain aspects of the publisher's mediation.

Interactions between Bidding Kit 2.0, client apps, and server-side platforms.

Bidding Kit 2.0 uses a client-side mediation solution, which means that the end user's device consolidates information and decides which provider will win the impression. Impartial client-side auctions allow all connected demand sources to bid for impressions using open real-time bidding (ORTB). Because these auctions rely on SDK integrations for ad rendering and signal collection, demand sources can use their own technology and retain direct relationships with publishers.

System Flow

Traditional mediation systems focus on three separate concerns:

  • Waterfalls managed according to historical averages
  • Ad load balancing between resources, UI, and yield
  • Display of ads by simple abstraction on top of ad SDKs

The following figure illustrates a standard flow of how a mediation system is integrated with Bidding Kit 2.0.

System flow

The basic flow consists of the following steps:

  1. On launch, your app's client-side mediation logic should retrieve the waterfall configuration from the mediation server.
  2. For each impression opportunity, client-side mediation makes a call to Bidding Kit 2.0. The bidding kit manager then:
    • Runs a first-price client-side auction and chooses a winner.
    • Dynamically merges the waterfall structure with information from real-time bids.
    • Reports the auction result back to the client, including the clearing price.
  3. The mediation system loads the winning ad in the background.
  4. Client logic requests to display the ad.
  5. The mediation system selects the demand sources to display the ad based on price and availability, and reports the final winner to all demand sources.
  6. The mediation system selects the appropriate adapter and requests that the ad be displayed.
  7. The requested SDK renders and displays the ad.