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.

Example

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.

Example

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.

Example

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.
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