How to implement server-side conversion tracking with Google Ads and Usercentrics CMP

The world is shifting away from third-party tags and data. Increasingly this will require companies to evolve their data strategies to embrace first-party data and a greater focus on user privacy and consent.

Server-side tagging (SST) is a key part of this evolution of data strategy. It enables more control over cookies and can integrate with any channel, like web, apps or smart devices.

This results in more consistent data across customer touchpoints, better automation, reduced costs, improved consent management across platforms, and provides a single source of information for legal audits. SST also integrates with data management technologies like customer data platforms (CDP) and data warehouses and offers an option to handle the Privacy Shield issue.

Like client-side tagging, server-side tagging enables data to be collected and delivered where it’s needed. However, with SST, the tag or pixel sends data to a server, like a web server, which then passes it to a destination server (or servers). There is one data stream enabling and centralizing control of data access for services like marketing technology partners and analytics providers.

A popular example of the use of server-side tagging is the tracking of conversions in Google Ads. For this purpose, two client-side tags are normally used. One that stores the Google click ID (“gclid”) in a cookie on the user’s device when an advertising campaign is called up, and another one that sends the conversion information directly to Google in the case of a conversion.

The integration of the server tag manager offers several advantages. The data from the user’s browser does not go directly to Google, but first to a dedicated server under an organization’s own control, which helps to bypass adblockers. Also, the cookie that stores the Google click ID can be generated by this tagging server and get transferred to the browser using an HTTP header. That offers several benefits, such as bypassing Safari’s maximum cookie runtime (Intelligent Tracking Prevention or ITP).

In the event that the owned server is hosted by a provider located entirely within the EU, it is possible to configure the server such that no unwanted data is transferred to unsecured third countries, such as the USA (Privacy Shield issue). And lastly, it also reduces the amount of Javascript code that the browser has to download and execute, which in turn leads to improved Core Web Vitals, and with that, better SEO performance.

Prerequisite for the implementation is a fully set up and configured Google server tag manager with GA4 conversion tracking, as well as a web/client tag manager. Note that while the example shown is commonly used, each server-side tagging setup is unique to individual company needs. This example is for educational purposes only and we cannot guarantee completeness or accuracy for individual use cases.

GA4 can be used for the transfer of information about pageviews and conversion. The transfer is also possible with other services, such as Universal Analytics or AT Internet, but for this article we will use GA4.

In order for the tags on the server to only trigger with consent, the current consent status for Google Ads must be sent to the server for the pageview as well as the conversion with the other GA4 data. For this purpose, you can add a parameter to the GA4 tags.

A variable can be defined as a value that reads the current consent from the data layer where it is provided by Usercentrics.

A simple data layer variable with the exact name of the service added in the Usercentrics Admin Interface is sufficient. (Note: variable name is case sensitive.)

This event parameter must be added to all tags relevant for Google Ads Conversion Tracking (e.g. pageviews, conversion).

The Conversion Linker tag, which will store the Google click ID in a cookie, must then be created on the server. There is a template for the tag from Google, which can be used for this:

The Conversion Linker tag should be triggered with every pageview.

As the trigger should only be triggered if consent is given, a variable is needed that can read out the consent status for Google Ads from the GA4 request. The most suitable variable type for this is “Event Data”, which can read the consent status from the event. The name of the parameter defined in the web tag manager must be used as the key path.

Another tag is needed to send the conversion to Google Ads. Google also offers a template for this. Conversion ID and conversion label must be configured in the tag settings. Optionally, a conversion value, currency, ecommerce information on product level (e.g. products sold, etc.) as well as customer- or user-provided data can be passed. The configured tag could look like this.

This time, an event with the name of the conversion is defined as the trigger, for example, “purchase” in the case of ecommerce. This trigger should also be restricted by the consent for Google Ads, so the same variable is used as for the Conversion Linker tag.

You should now have the following tags:

Web-Tag Manager:

• GA4 Pageview (with parameter for Google Ads Consent), triggered on every pageview
• GA4 Conversion (with parameter for Google Ads Consent), triggered on conversion

Server Tag Manager:

• Conversion Linker Tag, triggered on every pageview with consent for Google Ads
• Google Ads Conversion Tracking Tag, triggered on every conversion with consent for Google Ads

Preview mode on the server can be used to check whether the parameters from the GA4 tags arrive successfully on the server and whether the server tags are triggered as planned.

This article shows only one of many options that can be implemented with a server tag manager. There are a number of other popular use cases.

Conversion tracking with other advertising networks. Following the same logic, other vendors such as Meta (Facebook), AWIN or Trbo can also be connected to the server tag manager. However, by transferring data on the server side, the amount of Javascript in the web browser remains the same, which leads to improved core web vitals and thus better search engine placement.

(Basic) web tracking without consent / circumventing the Privacy Shield issue. By using a manual server hosted within the EU, personal information can be filtered out so that transmission to a vendor is possible without need for consent. In this way, together with Google Consent Mode, consent-free basic tracking can be made possible with GA4 or Universal Analytics, for example. Additionally, issues relating to the terminated Privacy Shield legal framework can be circumvented, as personal information can be cut off before sending data to the USA.

Enrichment of tracking data with additional information: On the server, not only can information be shortened, but also added. Tracking data can be enriched with additional information that is only available on the server side (e.g. customer IDs, technical website environment, etc.).

Tracking of Usercentrics consents in third-party analytics-tools: Usercentrics already offers a variety of analysis options in the CMP’s Admin Interface. However, with the help of a server-side tag manager, additional tracking of interactions can be done in third-party web analytics services.

In an ever-changing world that is shifting away from third-party data, server-side tagging can be the deciding factor in your data strategy. Server-side tagging provides more control over organizations’ own data and helps circumvent intelligent tracking prevention (ITP) and adblockers. It can also improve website performance and prevent unwanted data from being sent to third countries.

The client-side requests for consent for individual services and transmission to the server environment can be easily implemented with the Usercentrics CMP. By processing the consent on the server tag manager, organizations ensure that they always respect the users’ consent choices and are data compliant. This enables, for example, successful set up of conversion tracking in the server tag manager environment, and benefits from the many advantages of the technology.

Additionally, a specialized setup on a company’s server with a custom client can enable the enrichment of analytics data or preventing sending unwanted data to third countries (e.g. Privacy Shield issue). For individual setups, Usercentrics collaborates with experienced partners such as dwc, who use their knowledge of both server-side tagging and the CMP to provide the best possible advice and to raise customers’ tracking capabilities to the next level.

Contact our experts to learn how you can implement server-side tagging for your business.