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Optimize waterfall ad sources in mediation

Turn on optimization to allow AdMob to dynamically manage the order of an ad source in the mediation waterfall. #optimization

To help maximize revenue, consider turning on optimization for a third-party ad source or the AdMob Network.

What is optimization? 

Optimization helps ensure you’re getting a more accurate eCPM and eliminates the need for you to manually order your ad sources in the mediation waterfall. 

Turning on optimization allows AdMob to manage the order of an ad source in the mediation waterfall by adjusting its eCPM. AdMob uses historical data from the ad source to detect trends and changes, then updates the eCPM accordingly.

Consider using bidding to enable your third-party ad sources to compete in a real-time auction for your ad requests.

How optimization works

AdMob gathers an ad unit’s historical eCPM data by calling your third-party ad source’s API.

Note: You’ll need to provide your ad source’s credentials and map your ad units in order for AdMob to gather the data directly from the ad source.

Once AdMob has gathered enough data, the ad source’s eCPM and its placement in the waterfall is updated regularly. The mediation waterfall is optimized for each country.

Note: Not all ad sources support optimization. Review the list of third-party ad networks that support optimization to learn more about the available ad sources.

Optimize a third-party ad source

In order to optimize a waterfall ad source, you’ll need to input the ad source credentials. This allows AdMob to gather the historical eCPM and reporting data from the third-party ad source. 

You’ll also need to enter the mapping details for each ad unit. In most cases, these details will be available in your account with the ad source.

You can choose to optimize an ad source when you add it to a mediation group or you can edit it later to make changes to the optimization settings.

To update an ad source’s optimization settings after you’ve added it to a mediation group:

  1. Sign in to your AdMob account at
  2. Click Mediation in the sidebar.
  3. Select the mediation group with the ad source instance you’d like to optimize. 
  4. In the Waterfall ad sources table, click Edit next to the eCPM of the ad source. 
  5. Turn on the toggle next to eCPM optimization. 
  6. Enter an eCPM value to order this ad source while AdMob gathers enough historical data for optimization. 
  7. Enter the ad source's credentials
  8. Click Confirm

Optimization in progress

When you enable optimization, AdMob begins analyzing your app's traffic to understand the best way to optimize the ad source’s eCPM. During this analysis period, you may notice the “Optimization in progress" status appear in the ad source table. You may have this status for up to 3 days. 

Learn more about all of the possible optimization statuses.

Optimize the AdMob Network

When you turn on real-time eCPM (bidding) for the AdMob Network, it converts to a bidding ad source. AdMob will calculate its bid in real time. This means the AdMob Network will be re-evaluated and positioned in the mediation waterfall for each ad request matched to the mediation group it’s been added to. 

You can choose to optimize the AdMob Network when you add it to a mediation group, or you can edit it later to make changes to the optimization settings.

Optimization FAQs

What’s the difference between Observed eCPM and Optimized average eCPM?

Observed eCPM

You can review the observed eCPM metric in your reports. Observed eCPM is the estimated average eCPM you’ve received. For third-party ad sources, this value is provided by the respective third-party ad source. Observed eCPM will only be shown for ad sources which have optimization enabled.

Optimized average eCPM

You can review the optimized average eCPM in the mediation group page. This is the eCPM that’s used to determine the ad source’s placement in the mediation waterfall. AdMob updates the optimized average eCPM twice a day using historical data.

What happens when optimization is turned on?

AdMob will:

  • Manage the positioning of the ad source in the mediation waterfall.
  • Automatically make adjustments to the eCPM associated with the ad source based on traffic in your app, historical data, and information retrieved from the ad sources themselves.

I’m having an issue with optimization. What should I do?

Check the optimization status of your ad source instance. The status column should provide a status whether we were able to optimize your ad source or not. Learn more about all of the possible optimization statuses and what you can do. 

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