Question from Reddit:
I created a custom segment based upon certain website, I don’t see an option to add it for my campaign?
How do I do this? I would highly appreciate it.
Answer from Nabil:
The short answer is:
You’re running into a common distinction in Google Ads: Custom Segments (formerly Custom Intent or Custom Affinity Audiences) based on websites or interests can only be added at the ad group level, not the campaign level, for Search campaigns.
Furthermore, you need to navigate to the Audiences tab under the ad group, click the pencil icon to edit the audience segments, and select the list there.
You must also ensure the list is being added for Observation (to see performance data without limiting reach) or Targeting (to narrow your reach to only people in that audience), depending on your goal.
The long answer is:
That’s a great question, and it’s a very common point of confusion because Google Ads manages audience types at different levels and for different campaign types.
For your Search campaign, a Custom Segment that you built using specific websites or search terms is treated as a form of interest-based audience or an in-market audience, and these are managed at the ad group level, not the campaign level.
To add it, you need to go to your Google Ads interface, navigate to the specific Search campaign, then select the Ad Groups under that campaign.
Once inside the ad group, look for the Audiences section in the left-hand navigation panel.
Click on the pencil icon to Edit Audience segments, and then you’ll be able to select your custom audience and add it.
Crucially, on the right side of the screen, you will choose one of two settings: Observation or Targeting.
For most Search campaigns, you should start with Observation; this allows your ads to continue showing to all relevant users, but it lets you see how your custom segment performs and gives you the ability to set bid adjustments for users on that list.
If you choose Targeting, you will drastically narrow your reach because your ads will only show to people who are actively searching and are a member of that specific custom segment.
Looking beyond the native interface, if you find yourself struggling to manage many different audiences or you want to build audiences based on more granular, first-party data that isn’t fully captured by the standard Google Ads tags, an excellent, scalable solution is to combine the Google Ads API with a server-side tagging environment like Stape or Google Cloud Platform, managed by Google Tag Manager.
You can use GTM to capture rich user behavior on your site and send it to your server container.
The server can then use the Google Ads API to create and update Customer Match lists or other high-value remarketing lists instantly, based on your own internal customer data (like customers who viewed a specific product category) which is far more precise than a standard custom segment.
This gives you programmatically created, highly targeted audiences that are updated in real-time without relying solely on the client-side browser tracking, giving you a powerful, automated advantage for your bidding and audience strategies.
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