Set up a waterfall ad source

Waterfall ad sources rely on user-provided eCPMs or historical data to determine their order in the mediation waterfall. You can choose to manually provide the eCPM for the ad source, or you can turn on optimization, which allows AdMob to dynamically order this ad source in the mediation waterfall based on historical data. 

To set up a waterfall ad source:

1. Sign in to your AdMob account at https://admob.google.com.
2. Click Mediation in the sidebar.
3. Click the Waterfall sources tab. 
4. Click Set up ad source. 
5. Select the ad source you want to set up from the list that appears. Learn more about the ad sources available for waterfall mediation.
6. Click Next. 
7. If your ad source supports optimization:
   1. Enter the credentials for the ad source. Credentials are required to view reporting data from the ad source in your AdMob reports. Entering the credentials also allows you to optimize this ad source in a mediation group. 
   2. Review and check the Authorization checkbox to authorize AdMob and Google to access, manage, retrieve, and analyze data relating to your accounts with the ad source and represent that such authorization and access does not violate any of your third-party agreements. Once you’ve authorized this ad source, you won't be asked again.
   3. Click Save.
8. Add the ad unit mapping details for your ad units. You can also skip this step by clicking Skip and add the ad unit mapping details later.  

   If you want to call this third-party ad source multiple times in a mediation group, you’ll need to set up additional mappings for each ad source instance.

9. Click Save.

Add your ad source to a mediation group 

After you’ve finished setting up your ad source and mapping your ad units, you’re ready to add it to a mediation group. Learn how to create a new mediation group or follow the instructions below to add your ad source to an existing mediation group:

1. Sign in to your AdMob account at https://admob.google.com.
2. Click Mediation in the sidebar.
3. In the Mediation group tab, click the name of the mediation group to which you're adding the ad source. 
4. In the Waterfall ad sources table, click Add ad source. 
5. Find the ad source in the list that appears or begin typing the name of the ad source in the search box. Click Select next to the ad source you want to add. 
6. If your ad source supports optimization, the optimize toggle is on by default. If you don’t want to optimize this ad source, click the toggle to turn optimization off.
7. Enter a manual eCPM.

   • For optimized ad sources, this eCPM value is used to order this ad source while AdMob gathers enough historical data for optimization. Once this ad source is optimized, the optimized eCPM is used to order the ad source.
   • For ad sources without optimization, this eCPM value is used to order the ad source in the mediation waterfall.
8. Click Continue.
9. Select an existing mapping for your ad unit or click Add additional mapping to set up a new mapping. If you haven't set up any mappings yet, click Add mapping. 
10. Click Done.
11. Click Save. The mediation group will be saved.