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Google has released server-side tagging which allows Google Tag Manager (GTM) users to move measurement tag instrumentation from their website or app and into server-side processing containers via Google Cloud. As a trusted GMP partner, Cardinal Path had early access to this new capability and have had an opportunity to test it. We’re happy to share what we’ve learned, and help you figure out if server-side tagging is a good fit for you and your organization.

Why do this?  

Two primary reasons: performance and security. 

By reducing the number of network requests and javascript files you would normally load on the pages, you’ll get a faster loading website. This is a critical part of a good user experience, particularly for mobile users.

You have more control over the data you collect, which is becoming increasingly important in this age of data privacy and consent management.

How does it work?  

Instead of installing all your tags in your traditional GTM container, you’ll send one stream of data to your server-side container where it will relay that same data to any tag you wish. Google has provided an introduction to server-side tagging.

An example of a tagging configuration that uses a server-side container.

What are the activation steps?

Activating is relatively straightforward:

Step 1: Create a new “Server” container within your existing Google Tag Manager Account.

New “Server” option.

Step 2: Link the container to a Google Cloud Platform Project. This will require access to a billing account, so a credit card may be required. Don’t worry about charges yet, there are no costs until another step takes place. This allows you to evaluate in lower environments (i.e. a staging site) before committing to any charges.

Step 3 (Optional, but we recommend): Set up a custom domain. This lets you use server-side cookies which may allow you to circumvent some of the issues Safari has imposed recently with ITP

Step 4: Send data to your new container. This can be achieved by sending data from your existing Google Tag Manager container, a gtag.js library, or server side via Measurement Protocol.

Step 5: You are now ready to configure and publish your new container.

New Terminology: Client

The new container has a new configuration setting referred to as “Clients”.  

New “Clients” setting.

The role of the client is the process inbound data arriving into the server side container. While you may have many Clients, only one Client will process the inbound data. The containers will be pre-loaded with two Clients: Universal Analytics & App + Web.  

You will also have the option of creating your own Client, an example Client might be one that can process data from Adobe Analytics.


There are no upfront costs to set up your container. You’ll start by using the App Engine Standard environment. When it is time to deploy on production, you will want to upgrade to the Flexible environment. This upgrade is recommended as it will be able to handle various server loads and uptime will be more reliable than the Standard environment. Pricing will vary depending on usage.

Domain Setup

Cookies created using JavaScript have been further restricted by recent changes in browser updates where setting up a domain will allow for “server” cookies, specifically the cookie that stores the beloved “Client ID”.  Server-generated cookies benefit where they don’t have the same restrictions as scripted generated cookies such as the restrictions imposed by Safari OS which can expire cookies sooner than expected .

Google is now offering a method to change the tracking endpoint ( to an endpoint that you control such as I love the fact this is a 100% self-service process!

Steps for setting up a domain:

  • Verify domain ownership via Google Search Console
  • Configure domain in the “application settings” within App Engine
  • Add DNS entry to point to Google servers

Once the DNS propagates, Google will provide an SSL certificate free of charge, but you are also able to install your own if you prefer.

Who Will Benefit from Server-side GTM

Anyone with security or performance concerns should definitely consider using this feature. Another great feature of server-side GTM is the debugging tool, which allows you to verify what data is being collected. It offers similar debugging features as the web version. Implementations that use the Measurement Protocol will greatly benefit from these validation/debugging capabilities.

Consider installing both GTM solutions and then slowly migrate your tags to server-side to achieve benefits from both ends.