Overview of AdMob mediation

What is AdMob mediation?

Mediation is a feature of AdMob that helps you manage all of the ad sources you use to serve ads to your apps in one place. Using mediation, you can send incoming ad requests to multiple ad sources and help ensure you find the best available ad sources to fill the requests. Mediation will use mediation groups to try to help maximize your revenue by ranking all the ad sources based on optimized performance.


What are mediation groups?

Mediation groups are combinations of targeting settings that help to optimize the revenue generated by your ad units. You can create mediation groups ahead of time, then add ad units and ad sources as you go, or create them all at once. Instead of setting mediation options for each ad unit repeatedly, you can just set them once for your mediation groups, then add your ad units to the groups you want.

To find your mediation groups page, sign in to your AdMob account and click Mediation in the sidebar.

Once you've set up mediation in AdMob, you can use the Google Developers guide (Android, iOS) to implement mediation in your apps.

How do mediation groups work?

When an ad request is sent to AdMob from one of your ad units, AdMob mediation examines the ad request and compares it to the targeting settings of the mediation groups you've defined.

  • If the request matches the targeting for one of your mediation groups, that group will fill the ad request by serving an ad from one of its included ad sources.
  • If the request matches more than one of your mediation groups, AdMob will use the group priority to determine which group should fill the ad request. Conflicts between mediation groups should be avoided, if possible.
  • If the request doesn't match any of your mediation groups, it will be automatically filled by the AdMob (default) group, instead.

Note: Mediation groups don’t waterfall or daisy-chain from one to another. If an ad request can't be matched to a mediation group it will be filled by the AdMob (default) group. However, the ad networks included as ad sources within a mediation group do waterfall when trying to fill an ad request.


Here's an example:


A publisher has created an Android game app and wants to add 10 banner ad units. Because most of the app's users are Japanese, the publisher also wants to use a mediation group to manage the ad sources that serve ads to users in Japan.

First, the publisher creates all 10 ad units in AdMob. 
Then, the publisher creates 1 mediation group. They choose the following settings:
  • Format: "Banner"
  • Platform: "Android"
  • Name: "Japanese banner ads"
  • Location: "Japan" 

They add all 10 ad units to the mediation group. Then, they add and configure the ad sources--several third-party ad networks that perform well in Japan--and save the group.


Finally, the publisher implements the ad units and mediation in their app.

What is mediation group priority?

Priority tells AdMob which mediation group is more important to your revenue goals. When multiple mediation groups can be used to fill an ad request, AdMob uses the value in the Priority column to determine which mediation group should fill the ad request.

There are a few things to keep in mind when setting priority: 

  • When more than one mediation group matches the targeting of an ad request (location, platform, etc.), the mediation group with the highest priority (the smallest number) will be chosen to fill the ad request.
  • The highest priority you can set is 1. 
  • The lowest priority you can set is the number equal to the number of mediation groups you’ve created. Example: If you have 5 mediation groups, 5 is the lowest priority you can set. If you set priority to 8, it will automatically default to 5.

After an ad request is matched to a mediation group, the ad request will waterfall through that group's ad sources.


Here's an example:


AdMob receives an ad request from an Android user in Vancouver, Canada. The ad request matches 3 of the publisher's mediation groups: 
  • "Banner ads for Android in North America" (priority 3, uses InMobi, Flurry, and the AdMob Network)
  • "Banner ads for Android worldwide" (priority 5, uses AdFalcon, Flurry, and the AdMob Network)
  • "Banner ads for Android in Canada" (priority 1, uses Flurry, Chartboost, and the AdMob Network)
The mediation group "Banner ads for Android in Canada" will be chosen to serve the ad because its priority is 1, which is higher than the priorities of the other conflicting groups. The ad request will waterfall through the ad sources included in the mediation group: Flurry and then Chartboost and then the AdMob Network.

Avoiding conflict between mediation groups

You can avoid conflict by planning ahead. If you target a country or region, platform, or ad format explicitly in one mediation group, you may want to exclude it from the other mediation groups you create. 

In the example above, the publisher had already created a specialized group that targeted banner ad requests from Canadian Android users. They could have avoided conflict between groups by excluding Canada from the other Android banner ad mediation groups.

However, if you create many mediation groups to manage your ad sources, there will probably be conflict on occasion. It's important to consider the correct priority for your mediation groups to help ensure that AdMob can use them to try to maximize your revenue efficiently. 

AdMob (default) group

In most cases, an ad request received by AdMob will be compared to your mediation groups and filled by the group with the matching criteria. However, some ad requests won't match any of your mediation groups.

The AdMob (default) group automatically tries to fill any ad requests that aren't matched to any of your mediation groups. It sources ads directly from the AdMob Network.

The AdMob (default) group is already created for you in the Mediation groups tab.


Here's an example: 
A publisher has created the following 6 mediation groups in AdMob: 
  • Interstitial ads for Finnish Android users
  • Interstitial ads for Finnish iOS users
  • Interstitial ads for Norwegian Android users
  • Interstitial ads for Norwegian iOS users
  • Interstitial ads for Swedish Android users
  • Interstitial ads for Swedish iOS users

All 6 of these mediation groups exclude locations in other countries.

If someone using their app on an iOS device in Finland generates an interstitial ad request, it will be filled by the "Finnish iOS users" mediation group.
However, what if an Android user in Denmark generates an interstitial ad request?  The ad request doesn't match any of these groups, so it would be filled by the AdMob (default) group instead.

Previous version of AdMob

AdMob Mediation is a feature that lets you serve ads to your apps from multiple sources, including the AdMob Network, third-party ad networks, and house ad campaigns. AdMob Mediation helps maximize your fill rate and increase your monetization by sending ad requests to multiple networks to ensure you find the best available network to serve ads.

See the Google Developers guide (Android, iOS) for instructions on how to add the mediation SDK code into your app.

There are two types of mediation you can use, independently or simultaneously, in AdMob:

Some ad networks may allow SDK-less mediation.

Before using AdMob Mediation:

  • Confirm that the app isn't using AdMob Mediation via DoubleClick for Publishers (DFP) backfill to AdMob. The app should be calling AdMob directly through the Google Mobile Ads SDK.
  • If you're using smart banners, confirm that they're supported by the networks you're using for mediation.

Get started with AdMob Mediation now

Impression goal campaigns

Impression goal campaigns are house ad campaigns that serve ads to your app using your own inventory, free of charge. The impression goals that you set determine the target number of impressions that the campaign will serve during the duration of the campaign. You can use impression goal campaigns to promote your app or another advertiser's product. For example, you can work out a deal directly with an advertiser outside of AdMob to run their campaign in your app.

Impression goal campaigns are served via AdMob Mediation and take precedence over other ad sources in the mediation stack. If there are multiple impression goal campaigns, ad serving will rotate evenly through the campaigns. However, AdMob limits the number of impressions that can be served daily, based on the following calculation:

daily limit = impression goal / total number of days the campaign will run

After all impression goal campaigns are served (or the daily limit is reached), ad requests will be filled by eCPM-based ad sources, including the AdMob Network, the AdMob eCPM Floor Beta, third-party ad networks, and house ad campaigns. The eCPM value determines the order of the ad network to serve ads.

Ad sources ordered by eCPM

When you set up mediation, your settings tell AdMob how to choose between multiple ad sources. Currently, you can only allocate traffic based on the eCPM (effective cost per thousand impressions) value, which is an estimate of ad revenue. You can find the eCPM value of each ad network from the historical reports available through their websites or you can enable ad network optimization to allow AdMob to automatically obtain the eCPM value from each ad network.

The eCPM value determines the order of the ad network to serve ads. The ad network with the highest eCPM value is served first. If an ad network is unable to fill the request, AdMob tries the network with the next highest eCPM. It continues down the list until it finds a network to fill the request. Ad networks with the same eCPM value are distributed evenly. This list or ranking of ad networks is often called the mediation stack.

You can enable AdMob to bid alongside the other ad networks on a per-impression basis. That means, AdMob Network will be dynamically positioned in the mediation stack.


SDK-less mediation

AdMob currently supports SDK-less mediation for certain ad networks (Android, iOS). SDK-less mediation allows you to access demand without needing to integrate individual ad network SDKs into your apps. This means you can access additional networks for mediation without worrying about keeping third-party SDKs up to date.

To use this feature, select the "SDK-less" option when setting up SDK-less mediation. You don't have to install or maintain any SDKs or adapters for a network you've set as "SDK-less," however, you must still install the Google Mobile Ads SDK:

  • Android:
    • 5.0 or later (devices with Google Play Services)
    • 7.8 or later (devices without Google Play Services)
  • iOS:
    • 7.2.1 or later

In the mediation table, mediation network line items using SDK-less mediation will show "SDK-less" in their titles.


Rewarded mediation

Rewarded video ad units allow you to reward users with in-app items for watching video ads. You can specify the reward values associated with the ad units in your app and set different rewards for different ad units.

To use rewarded mediation, follow the instructions to set up AdMob Mediation. Be sure to follow the Google Developers guides (Android, iOS) and select ad networks that serve rewarded video ads (Android, iOS).


Ray is an AdMob Mediation expert and author of this help page. Help him improve this article by leaving feedback below.

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