Map your ad units

Mapping your ad units is an essential step in mediation. To map your ad units, you’ll need to know the mapping details for the ad units. Mapping details are the unique identifiers for the ad units created in your third-party account. Each ad source may have different required mapping details, and can be identifiers such as App ID or Slot ID. 

Adding your mapping details allows AdMob and third-party ad sources to work together to fill your impressions. It also helps ensure accurate reporting and optimisation for third-party waterfall ad sources in your AdMob account. 

When you map your ad units by ad source, you won’t have to map the ad units again when you add the ad source to a mediation group. Instead, you’ll be selecting which ad unit mapping to use when you add the ad source to a mediation group. Also note that some bidding ad sources do not require ad unit mapping.

Add additional mapping for an ad unit 

Adding additional mappings allows you to call a third-party waterfall ad source more than once in the mediation waterfall. Each ad source instance in a mediation group must have its own unique mapping. This means that you’ll need to set up an additional ad unit in your third-party ad source account before you add an additional mapping in your AdMob account. 

To set up additional mapping, follow the instructions below. Note that bidding ad sources only use one mapping per ad unit. 

Manage your ad unit mapping details

You can edit your ad unit mapping details or add additional mappings for your ad units in the Ad source page of your account. Complete the following steps to add or edit ad unit mappings. 

1. Sign in to your AdMob account at https://apps.admob.com.
2. Click Mediation in the sidebar.
3. Click the Bidding sources tab to edit mapping details for a bidding source. Click the Waterfall sources tab to edit or add additional mappings for a waterfall source.
   Note: Bidding ad sources can only have one mapping per ad unit.
4. Select the ad source with the mapping that you’d like to add or edit. 
5. Click the Ad unit mapping tab. 
6. Find the app with the ad unit mapping that you’d like to add or edit. Click .
7. Click Manage mapping to edit your mappings. To add additional mappings, click Add mapping. Note that you set the name of the ad unit mapping. 
8. Once you’ve finished making changes, click Save. 

Troubleshoot mapping & optimisation issues

You can check the status of your ad source’s ad unit mapping and optimisation in the ad source page of your account. The table below shows the statuses and what they mean.

Status	What it means
	This ad unit is successfully mapped.
–	The ad unit mapping hasn’t been verified yet. This status occurs when you’ve recently created an ad unit or recently added mapping details.
Incorrect mapping	The mapping details that you provided are incorrect.
Missing mapping	Some required mapping details are missing. Enter the mapping details for each ad unit for third-party reporting and optimisation to begin. In most cases, these details will be available in your account with the ad source.
Not able to optimise	AdMob was not able to optimise this ad source.
Not enough impressions	Your ad unit doesn’t have enough impressions. Your ad unit must have a minimum of 100 impressions per day for three days out of the last 10 days in order for all of your ad units to be optimised.
No requests	No requests were made to this instance of the ad source. This could be due to: The mediation group priority is too low. This ad source instance is ordered too low in the mediation waterfall. Requests are likely to be filled by higher priority mediation groups and ad sources that are higher in the mediation waterfall.
Optimisation in progress	You’ve entered credentials for this source, but optimisation and eCPM updates for reporting haven’t started yet.  When optimisation is enabled and credentials are entered, there may be a delay while AdMob gathers data. Optimisation will begin automatically once AdMob has gathered enough data. This can take up to three days.