Google Ads conversions and Enhanced Conversions server-side

When someone clicks an ad, the landing page URL carries a gclid. The Conversion Linker stores it in a first-party cookie (_gcl_aw). When the visitor buys, the GA4 purchase hit reaches your server container, and the Google Ads Conversion Tracking tag there sends the conversion to Google Ads with the click information, the order value and, with Enhanced Conversions, hashed customer data.

• Web container: a Conversion Linker tag and the GA4 tags you already have.
• Server container: a Conversion Linker tag, a Google Ads Conversion Tracking tag and, if you run remarketing, a Google Ads Remarketing tag.
• Google Ads: a conversion action with Enhanced Conversions turned on.

In the web container the Conversion Linker reads the click ID from the landing page URL and saves it. In the server container it lets the tagging server handle the Google Ads cookies on sgtm.example.com, so they are set first-party by your own domain.

1. 1 In the web container create a tag of type Conversion Linker, trigger it on All Pages and save.
2. 2 In the server container open Tags, click New and choose Conversion Linker.
3. 3 Trigger it on every GA4 hit: a trigger of type Custom that fires on Some Events with Client Name equals GA4. The trigger from lesson 4 works as is.
4. 4 Save the tag.

First get the two IDs of your conversion action. In Google Ads open Goals, then Conversions, open the purchase conversion action and look at its tag setup for Google Tag Manager. It shows a Conversion ID (the number in AW-XXXXXXXXX) and a Conversion Label.

1. 1 In the server container create a tag of type Google Ads Conversion Tracking.
2. 2 Enter the Conversion ID and Conversion Label from Google Ads.
3. 3 Check the value, currency and transaction ID fields. By default the tag reads them from the event data (value, currency, transaction_id) that the GA4 purchase hit carries. Fill them in only if you need different values.
4. 4 Create a trigger of type Custom that fires on Some Events with two conditions: Client Name equals GA4 and Event Name equals purchase.
5. 5 Name the tag, for example Google Ads - purchase, and save.

Google Ads uses the transaction_id to drop duplicate conversions for the same order, so send the real order number, as in the previous lesson.

Enhanced Conversions add customer data from the order (email, phone number, name and address) to the conversion. Google matches it with signed-in Google accounts, which recovers conversions that cookies alone miss. Google tags normalise the values and hash them with SHA-256 before they are sent to Google.

Push the data with the purchase, in a user_data object next to ecommerce:

window.dataLayer = window.dataLayer || [];
window.dataLayer.push({ ecommerce: null });
window.dataLayer.push({
  event: 'purchase',
  user_data: {
    email: '[email protected]',
    phone_number: '+48123456789',
    address: { first_name: 'Jan', last_name: 'Kowalski', postal_code: '00-001', country: 'PL' }
  },
  ecommerce: {
    transaction_id: 'T-10293',
    value: 129.90,
    currency: 'EUR',
    items: [{ item_id: 'SKU-1', item_name: 'Shoes', price: 129.90, quantity: 1 }]
  }
});

1. 1 In the web container create Data Layer Variables for the fields, for example user_data.email, user_data.phone_number and user_data.address.postal_code.
2. 2 Create a variable of type User-Provided Data, choose manual configuration and map each field (email, phone, first name, last name, postal code, country) to the matching Data Layer Variable.
3. 3 In the Google tag add a configuration parameter user_data with the User-Provided Data variable as its value. If you only want it on the purchase, add user_data as an event parameter of the GA4 event tag instead.
4. 4 In Google Ads open Goals, then Settings, expand Enhanced conversions for web, turn it on, choose Google Tag Manager as the method and accept the customer data terms.

The data now travels with the GA4 hit to sgtm.example.com, and the Google Ads Conversion Tracking tag in the server container sends it on with the conversion. You do not configure anything extra in the server tag.

The GA4 hit carries the visitor's consent state to the server container, and the Google Ads tags there respect it. For a full conversion with click cookies and customer data, ad_storage and ad_user_data must be granted, as set up in lesson 6.

• ad_storage denied: no Google Ads cookies are read or written, so the conversion cannot be tied to the click through them.
• ad_user_data denied: user-provided data is not used for advertising, so Enhanced Conversions have nothing to match.
• ad_personalization denied: the visitor is not added to remarketing audiences.

Open Preview in both containers. Land on the site with a test parameter such as ?gclid=test123, accept all consent, and place a test order.

• Web preview: the Conversion Linker fires on page load and the _gcl_aw cookie exists on your domain.
• Server preview: on the purchase event both the Conversion Linker and Google Ads - purchase are under Tags Fired.
• Server preview: the Outgoing HTTP Requests show a request from the Google Ads tag to a Google Ads domain such as googleadservices.com with a successful status.
• Server preview: the event data contains user_data, and value, currency and transaction_id are set.
• Google Ads: after a few days the conversion action and its Enhanced Conversions diagnostics show recorded conversions and matched customer data.