Create a mediation group

After you’ve created your ad units and set up your ad sources, you’re ready to create a mediation group. You’ll need to create a mediation group for each of your ad formats. You’ll also need different mediation groups for the platform (Android or iOS).

Complete the steps below to create a new mediation group: 

1. Sign in to your AdMob account at https://apps.admob.com.
2. Click Mediation in the sidebar.
3. In the Mediation groups tab, click Create mediation group. 
4. Select an ad format.
5. Select a platform.
6. Click Continue.
7. Enter a name for your mediation group. It should be descriptive so that you can find it in the mediation groups table later.
8. Select the locations that you’d like to target or exclude from this mediation group.
9. For iOS apps, you can also select whether you want to target ad requests based on the availability of the IDFA. Learn more about mediation groups for IDFA.
10. Click Add ad units.
11. Select the ad units that you want to associate with this mediation group. When AdMob receives ad requests from the selected ad units, AdMob will try to match the requests to the mediation groups that target those ad units.
12. Click Done.

13. Add some ad sources to your mediation groups. You can add bidding sources, waterfall sources or custom events:

    Add a bidding ad source to a mediation group

    1. In the Bidding ad sources table, click Add ad source.
    2. 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. 
       If you haven’t set up a partnership with this ad source, follow the prompts to sign a partnership agreement and acknowledge the bidding agreement.
    3. 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. 
    4. Click Done.

    Add a waterfall ad source to a mediation group

    1. In the Waterfall ad sources table, click Add ad source. 
    2. 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. 
    3. If your ad source supports optimisation, the optimise toggle is on by default. If you don’t want to optimise this ad source, click the toggle to turn optimisation off.
    4. Enter a manual eCPM.

       • For optimised ad sources, this eCPM value is used to order this ad source while AdMob gathers enough historical data for optimisation. Once this ad source is optimised, the optimised eCPM is used to order the ad source.
       • For ad sources without optimisation, this eCPM value is used to order the ad source in the mediation waterfall.
    5. 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. 
    6. Click Done.

    Add a custom event to a mediation group

    1. In the Waterfall ad sources table, click Add custom event. 
    2. Enter a descriptive label for the event. 
    3. Enter a manual eCPM to use for this custom event. The eCPM will be used to dynamically position the event in the mediation waterfall where it will compete with other ad sources to fill ad requests. Additionally, the eCPM will be factored into estimated earnings in the Ads Activity report and LTV metrics in the cohort report.
    4. Click Continue.
    5. Select an existing mapping to use for this custom event or click Add mapping to set up a new mapping. To use multiple custom events, you’ll have to create an additional mapping for each custom event.
    6. Click Done.

    When an ad request is received, the ad sources will compete to fill the request. You can always edit a mediation group to add or remove ad sources.

14. Click Save. The mediation group will be saved.
15. If you haven’t already implemented mediation in your apps, use the Google Developers guide to implement it now. If you don't complete this step, mediation won't be able to fill incoming ad requests.
    • iOS
    • Android