Set up automatic Google Customer Match Lists

In this article, we consider in detail Google Ads/Display & Video 360 feature - Customer List, the audience list built through Google Ads Customer Match feature. We will explain what it is, how it works, and how to set up an automated workflow for creating and populating the Customer List using the Google Data Manager API Customer Match tag or Stape Conversion Tracking apps for CMS and CRMs.

Customer List is an audience targeting feature in Google Ads/Display & Video 360. It allows you to upload customer data (such as email addresses, phone numbers, and addresses) to Google's platform. This list is built through the Google Ads Customer Match process, which matches your uploaded data against signed-in Google accounts. The resulting Customer Match lists are used in Smart Bidding and optimized targeting. When you create a campaign, you can use this data to target a specific audience or exclude some audience segment.

Customer List can be found and created in the Google Ads admin → Tools → Shared library → Audience manager → Create remarketing list → Customer List. This is one way to view your Customer Match Lists in Google Ads, though the manual path is inefficient compared to automated setup.

However, creating Customer Lists manually is inefficient - in this article, we show how to configure automated workflows with Customer Match for generating and populating Customer Lists.

Google Customer Match is the underlying mechanism behind the Customer List feature. It uses first-party data you provide — email addresses, phone numbers, or mailing addresses — to match your existing customers or leads with their signed-in Google accounts. Google hashes this data before matching it, so raw customer information is never exposed.

Customer Match Google Ads can be used for several purposes: building remarketing audiences from existing customers, creating similar/lookalike audiences based on your customer base, and excluding existing customers from acquisition campaigns. The feature requires compliance with Google's Customer Match policy, which mandates that data be collected with proper consent and used only for permitted purposes.

Firstly, you provide the data to Google Ads/Display & Video 360. You can manually upload a CSV file that includes the data on your users or connect the data source from the list in Google Ads/Display & Video 360. 

Other options to provide data are by using the Google Data Manager API Customer Match tag or the Stape Conversion Tracking apps for CMS/CRM (we describe their configuration in detail below). The benefit of these options is that you don’t need to do any manual actions, such as data gathering, formatting, and file upload in Google Ads/Display & Video 360. Everything is automated - creating the Customer List and adding user data to it.

Then, you set up or modify a campaign to execute the segment from the Customer List.

While Customer Lists help you target audiences with online data, many businesses also need to track sales that happen offline — such as phone orders, in-store purchases, or upsells. Google Data Manager API Conversion Events tag lets you send this information directly from your server GTM container to Google Ads, removing the need for manual file uploads. This improves attribution across online and offline touchpoints and allows Google’s bidding algorithms to optimize for customers most likely to convert. 

We have a detailed guide on how to configure the Google Data Manager API Conversion Events tag to track both online and offline conversions.

Regardless of the method you choose to create and fill the Customer List in Google Ads/Display & Video 360 - Google Data Manager API Customer Match tag or CMS/CRM app, you will need the following:

• Configured the server GTM container.
• Configured data sending from the web to the server GTM container. You can set up server-side Google Analytics 4 or Data Tag/Data Client.

You must configure one of the available authentication methods:

• Stape Google Connection (recommended) - the easiest way to handle the authentication. You just need to activate the Dada Manager API Connection in the Stape admin account.
• Own Google Credentials - if you don't use Stape's services or have a free plan on Stape, opt for this authentication method.

Select the authentication method that suits you best and follow the instructions:

You can complete the setup by installing the Google Data Manager API Customer Match tag or using Stape's CRM/CMS applications. Both approaches let you build Customer Match Lists in Google Ads automatically. Select the best-fitting option below, and follow the instructions:

To populate the Customer Match list, you need to accept a few terms of use:

• Customer Match terms.

It's a legal agreement within Google Ads where you confirm that any data you upload has been collected in compliance with Google’s policies (first-party only, clear opt-in). You can read more about the Customer Match policy on Google's end.

How to fix: the Customer Match terms usually pop up when you create the Customer Match list for the first time. Later, it must reappear; be sure to confirm that you comply with the policy.

• Enhanced conversion terms.

Enhanced Conversions in Google Ads sends hashed first-party data (emails, phone numbers) from your website to Google to "fill in the gaps" when cookies are blocked. That's a list of terms that allows Google to use this hashed data to match conversions to signed-in Google accounts.

How to fix: go to the Goals section → Settings → Enhanced Conversions. Check the box next to Turn on enhanced conversions. A window with terms must pop up; be sure to accept the terms.

Note: if your conversions are managed via the Manager Account (MCC), the customer data terms must be accepted from the manager’s account.

Enhanced Conversions for Leads (ECfL) is the specific feature that allows Google to attribute conversions using first-party data (like hashed emails) rather than just Google Click ID (GCLID). ECfL provides the framework to match CRM data using hashed first-party identifiers (like emails) instead of cookies or click IDs.

How to fix: go to the Goals section → Settings → Enhanced conversions for leads. Check the box next to Turn on enhanced conversions for leads. A window with terms must pop up; be sure to accept the terms.

To link a third-party tool (like Stape) to your Google Ads account via the API, the user account needs specific permissions. Lower access levels (like Read-only or Billing) cannot grant the necessary scopes for the Data Manager API to "write" or "upload" data to the account.

How to fix: Obtain Standard or Admin access to authorize the OAuth flow.

If you encounter the error says REQUIRED_FIELD_MISSINGThe reason is often that you selected a conversion type that requires a Transaction ID, but didn't provide one in the tag.

The requirement is determined by the Conversion Action Type:

• Website (any online conversions) - a transaction_id is mandatory.
• Offline (import from clicks) or enhanced conversions for leads - a transaction_id is optional.

For more info on when transaction_id is required, refer to Google's documentation.

If you are reporting an online "Website" conversion, you must provide a transaction_id regardless of whether the event is a purchase, a lead, or any other type.

How to fix: You need to provide the transaction_id.

Be sure to have a variable that will grab transaction_id in your Google Conversion Events tag.

The variable configurations:

• Variable Type - Event Data
• Key Path - transaction_id

The error INVALID_ARGUMENT for ad_personalization or ad_user_data points to consent. It means that the consent signal was either missing or sent in a format the API didn't recognize.

Google can process only three values:

• CONSENT_GRANTED
• CONSENT_DENIED
• CONSENT_STATUS_UNSPECIFIED

As provided in the tags:

How to fix: check whether you specified the consent status in the Request-level Consent section of the tag.

If you are dynamically viewing the consent status and using a variable in the Request-level Consent section, you need to transform the values into the appropriate ones that will be understandable for Google. For this purpose, use the LookUp variable.

Setting up automated Customer Lists in Google Ads/Display & Video 360 — built through the Google Ads Customer Match process — using the Google Data Manager API Customer Match tag or Stape's CMS/CRM apps significantly simplifies the audience targeting. By replacing manual uploads with automated syncing, Google Customer Match ensures your campaigns always use up-to-date customer data.

Whether you're using the server GTM tag or Stape's apps for WooCommerce, Shopify, HighLevel, or HubSpot, these integrations help you create and populate the Customer List in Google Ads/Display & Video 360.