Set up Google Tag Manager server-side tracking with Google Cloud Run

Table of Contents

• Prerequisites
• Terms
  • Tagging Server
  • Web container
  • Server container
  • Client
  • Transformations
• Sources of the instructions
• Create a Google Cloud project
  • Create the server container in Google Tag Manager
    • GA4 Day
    • Google Ads
    • Meta Conversion API
  • Linking web and server containers in the GTM
• Setting up Cloud Run in the Google Cloud
  • Preview Server
  • Tagging Server
  • User-defined domain
• Tests / Preview
• And afterwards
  • Controls
  • Deactivate logging
  • GA4 tags web and server in parallel
• Excursus: Adding your own tracking subdomain to a Google Cloud service
  • Set up a separate subdomain for the tagging server
• Your turn
• Do you need support?

Prerequisites

You know what it's all about. You want to lose less data during tracking, reduce any tracking brakes in the website and be able to act flexibly. That's why you want to say goodbye to client-side tracking and switch to server-side tracking.

What you need to set up server-side tracking with the Google Cloud:

• One Tracking domaini.e. usually a subdomain of your domain (e.g. https://metrics.IhreDomain.com)
• A Google Cloud Project - here you set up the tagging server
• One Credit card as an indication of the payment method in the billing account in the Google Cloud
• One Google Tag Manager (GTM) server container
• One Google Tag Manager (GTM) web container
• One Google Analytics 4 Property

The following data will be generated or required in the course of your work:

Cloud project ID
GA4 Measurement ID
GTM Webcontainer ID
GTM Server Container ID
Container configuration
Preview server URL
Tagging Server URL
Tracking subdomain

In these instructions, I assume that there is already a functioning GA4 Day in a Google Tag Manager container that stores data in a Google Analytics 4 Property sends. I refer to this GTM container as Web container.

Terms

Server-side tracking requires a tagging server and two Google Tag Manager containers:

Tagging Server

This server runs in the Google Cloud (or a platform from another provider). The server container of the Google Tag Manager is located in the tagging server. Ideally, you should use your own Tracking subdomain as the URL of the tagging server, thus avoiding the Google Cloud Server original address in the form of https://1a2b3c-4d5e6f.uc.r.appspot.com.
You will probably have to set up your own tracking subdomain (e.g. metrics.yourdomain.com) first (see Digression at the end of the article).

Web container

The GTM web container contains the web-side GA4 tag, which basically sends data to Google Analytics 4. However, with server-side tracking, the data is no longer sent directly to Google Analytics 4, but first to a client located in the GTM server container on the tagging server.

Server container

The GTM server container is set up in the tagging server. It contains a client that receives the GA4 tag requests from the web container.

Client

The client is located in the server container on the tagging server. It should receive the requests that arrive from the web container and possibly manipulate them (e.g. remove the IP address) before forwarding the requests to the server-side GA4 tag or the server-side Google Ads conversion tag (such data manipulation can be done with Transformations are made). Only the server-side GA4 tag or the server-side Google Ads conversion tag transmit the - possibly transformed - data to Google Analytics 4 or Google Ads.

Transformations

You can set up transformations to manipulate (reduce or enrich) the data before it is sent to Google Analytics 4.

Sources of the instructions

These instructions are based on the Original sources in Google Developers area - in the guidance of Michaela Linhart and Matthias Hausdorf. You can also find more explanatory details there if you need them.

Another important source is the article by Julius Fedorovicius (Analytics mania): "Introduction to Server-side tracking in GTM".

There are of course many more articles and instructions on the subject, but you should note the date of the articles. Some screenshots no longer correspond to the current (February 2024) reality.

Create a Google Cloud project

Use the URL https://console.cloud.google.com/projectcreate and create a new project in the Google Cloud. The tagging server will later be created in this project.

You can freely assign the name (in the example it ends with "SST Cloud Run").

In the example shown, the project ID ends with "...-sst-cloud-run". I save the project ID in the note text file (see above) because the project ID can often be needed again later.

Leave the storage location set to "No organization".

Now it's time to set up the invoice data under https://console.cloud.google.com/billing/. If you already have an invoice account, this will already be linked to your new project. Otherwise, create a new invoice account by clicking on "CREATE ACCOUNT".

Select the correct currency and enter all the necessary company, contact and credit card details, this is the only way to actually activate billing. 

In the Console Dashboard of the project you can always see all important entries.

https://console.cloud.google.com/home/dashboard?project=project-ID

Create the server container in Google Tag Manager

In the Google Tag Manager (https://tagmanager.google.com/#/home) to create a new container for use on the tagging server.

You need this server container additional to a web container. This means that a total of two containers are ultimately required in the case of server-side tagging. In the website itself only the code for the web container be installed. You will no longer find any installation code for the server container.

After creating the container, select Provide tagging server manually. Manual provisioning requires a lot more manual work (this article is rather long), but gives you full control over the service infrastructure. For example, you can leave the incoming data in Europe.

Save the code received from "Your container configuration" in the process-accompanying text file.

If you now call up the workspace and select the menu item Clients you will already see a client for Google Analytics 4 with the name GA4. This client will be executed later in the tagging server. It receives the data from the web-side GA4 tag and forwards it to the server-side GA4 tag. The server-side GA4 tag then forwards the data to the Google Analytics 4 property.

GA4 Day

Next, set up the GTM server container one GA4 Day with a trigger under the menu item Tags in.

The Trigger is of the trigger type User-definedand looks like this:

So the condition is: Client name - is the same - GA4

This means that data may only be forwarded to Google Analytics 4 if it is available from client GA4.

How to access the integrated variable Client Name under the conditions for Some events:

Then select the integrated variable Client Name from.

And this is what the server-side GA4 tag looks like. The GA4 measurement ID is used in the example as a variable of type "constant" so that it can be changed centrally at a later date.

Google Ads

You can also transfer the tag for Google Ads to the server container. In this case, you must all Google Ads conversion tags together with the Conversion Linker ("conversion link") from the GTM web container to the GTM server container relocateThese will therefore no longer be in the web container.

Meta Conversion API

And also for Facebook can be used to set up better tracking than the Meta Pixel with the help of a server container. The Conversion API enables a direct and more reliable connection of the marketing data of your website or online store with Meta. 

More on this in the Meta Business help on the topic of Conversion API and in the corresponding Meta guide. Of course there are also detailed instructions at Thomas Hutter.

Linking web and server containers in the GTM

You should already have a Web container in the Google Tag Manager, in which a GA4 Day exists. We have assumed this. You only need to add the information to send the data to your tagging server to this tag.

Create a GA4 tag in your GTM web container to send data to the tagging server. This additional GA4 tag will contain the GA4 measurement ID of the data stream of your new SST property. Add the following configuration parameters to this new GA4 tag server_container_url add. Enter the full URL of your new tracking subdomain as the value. This allows the traffic to be sent to the tagging server.

If it is possible on your website, enter the Tracking subdomain in the container code instead of the server googletagmanager.com in.

(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start': new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0], j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src= 'https://metrics.yourdomain.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f); })(window,document,'script','dataLayer','GTM-ABCD1234');

If you use the highly recommended plugin GTM4WP for this, you will find the change option under Advanced.

The server-side tracking also works with www.googletagmanager.com as a tracking domain, but then you do not have the advantage of using first party cookies. These are cookies that are set by your website and are therefore usually accepted by the browsers of website visitors.

Now add the additional client "Google Tag Manager: Webcontainer" to the GTM server and enter the ID of the GTM Webcontainer in the field Permitted container IDs option. This allows the GA4 client in the server container to receive data from your web container.

Setting up Cloud Run in the Google Cloud

The use of the service Cloud Run for the installation of the Tagging Server is strongly recommended. The costs are lower than when using the service API Engineand will only amount to a few dollars per month for websites that are not heavily visited. Michaela Linhart speaks in her guide of about 5 USD/month for her blog, which is certainly well visited Analytics box.

To manually create the tagging server with Google Cloud Run, we follow the Manual setup guide from Google.

Two servers are set up:

• Preview Server (Preview Server)
• Tagging Server

Preview Server

You need your own preview server, as the GTM preview is no longer possible in the usual form with server-side tracking.

In the Google Cloud (menu item Cloud Run), create a new Google Cloud Run service (ENABLE APIS AND SERVICES).

Click NOT to use quick start.

You can now use what is known as a Docker image, which is offered by Google. Such Docker Images are a kind of container for complex applications that can be easily transported and installed as files. 

Enter the following Docker Image URL under Container image URL in:

gcr.io/cloud-tagging-10302018/gtm-cloud-image:stable

Before clicking on CREATE, you must make any adjustments to the settings.

Service name: Enter a descriptive name with "-preview" (e.g. ss-gtm-preview)

Region: europe-west1 (Belgium)

Authentication: Allow unauthenticated calls

Minimum number of instances: 0

Maximum number of instances: 1

Scroll further down Containers, volumes, network, security on.

Under "Variables and Secrets", enter the variable CONTAINER_CONFIG and add the Configuration ID of the server GTM (the long letter/number code from the GTM server container settings) as its value.

Enter a variable RUN_AS_PREVIEW_SERVER with the value "true".

To repeat:

CONTAINER_CONFIG	[Configuration ID of the server GTM]
RUN_AS_PREVIEW_SERVER	true

Then check all the settings again very carefully and only then click on CREATE. The setup will take a few minutes.

Then copy the URL of the preview serverand save it again in your accompanying text file.

Tagging Server

You need another Cloud Run service for this, again with the same Docker image as for the preview server:

gcr.io/cloud-tagging-10302018/gtm-cloud-image:stable

Service name: Enter a descriptive name without "-preview", e.g. ss-gtm

Region: europe-west1 (Belgium)

Authentication: Allow unauthenticated calls

Minimum number of instances: 1

Maximum number of instances: 10 (to keep costs under control for "normally" visited websites)

Fold Containers, volumes, network, security on.

Under "Variables and Secrets", enter the CONTAINER_CONFIG variable again and add the Configuration ID of the server GTM (the long letter/number code from the GTM server container settings) as its value.

Enter a variable PREVIEW_SERVER_URL with the value of the previously received Preview server URL in.

To repeat:

CONTAINER_CONFIG	[Configuration ID of the server GTM]
PREVIEW_SERVER_URL	[the URL of the preview server]

Then check all settings again very carefully and only then click on CREATE.

Copy the URL of the tagging server and save it in your accompanying text file. You will no longer need it to hand, but for the sake of completeness and for the record.

User-defined domain

Now add your tracking subdomain (metrics.yourdomain) to the services. This step has proven to be the trickiest in practice. It simply requires a little patience and possibly several attempts.

In the Cloud Run service, click on Manage user-defined domains and on Add assignment. Select here as a service the tagging server serviceNOT the preview service. Then click on "Cloud Run domain mappings.

In the following screen, select the tracking subdomain you have already set up (e.g. metrics.yourdomain.com). If this has not yet happened, select "Confirm new domain ..." instead and start the described below process, i.e. add your tracking subdomain as a custom domain to the Cloud Run service.

Click on DONE to return to the list of domain assignments.

Wait until the assignment is complete (no more rotating symbol visible), this will take a good 15 minutes or more.

Even if you already see the checkmark, you will have to wait a little longer. Do the following test. Call up your tracking subdomain with an appended "/healthy".

https://metrics.IhreDomain.com/healthy

Only when you receive an "ok" as a result does the server container appear to have been set up. You do not need to continue until this is the case.

Add the URL of your tracking subdomain (in our example metrics.yourdomain.com) to the container settings of the server container in Google Tag Manager.

Tests / Preview

To see whether it really works, open the Preview of the web container. Open a page of your website in it. The web container tag for GA4 should appear under "Tags Fired".

Switch back to the Tag Manager window of your browser, open the Server containerand then its Preview.

Switch to the page of the website you have already opened in your browser and reload it. Or you can load your website in a new browser window.

In the Preview of the server container you should now receive a result similar to the following. In the sidebar on the left, you should see at least one call of the type collect?v=2&tid=G-.... see.

In the example, the GA4 client sends data to your Google Analytics 4 property.

Complete success!

Please note that the Real-time report in Google Analytics 4 reacts much more "sluggishly" than with client-side tracking.

You have reached your goal!

And afterwards

Controls

Under (Cloud Run) Service details / Measured values you can see the utilization of the server at any time.

The first field shows the "Number of requests".

Another field shows the "Number of container instances". You should check this data after a week or so to see whether 10 instances are actually necessary for your website; you may be able to manage with fewer, or you may need more. These service settings can also be changed at a later date (Edit service configuration).

If necessary, regularly check the Costs in the Invoice account.

GA4 tags web and server in parallel

Run the original GA4 tag in the web container for a while in parallel with the new GA4 tag, which sends data to the server container. This allows you to see whether the data collection is working. However, you will notice that fewer new users are detected with server-side tracking. This is because server-side tracking is better at recognizing returning users.

If you are sure that everything is working, replace the Google Analytics 4 data stream measurement ID in your GA4 tags (web and server container) with the previously used measurement ID. From now on, the data collected with server-side tracking will end up in your usual GA4 property.

Excursus: Adding your own tracking subdomain to a Google Cloud service

Set up a separate subdomain for the tagging server

To the instructions on developers.google.com

When you set up a tagging server for the first time, it is hosted in a domain provided by the cloud provider (in our case, this is Google). In order for data to be sent to the server container in the first-party context (first-party cookie), your tagging server and your website must be on the same domain run.

We select the implementation option Subdomain from.

In the Google Cloud Console, call up the Settings (sidebar on the left, at the very bottom) the tab User-defined domains on. You must be in the project that corresponds to your container ID.

Select "Add custom domain".

In the dropdown, select "Confirm new domain ..." and enter a subdomain that you want to use for this in the field below. In many cases, you use a subdomain of your choice called metrics (others use data, ssgtm or similar). metrics is also used in this example.

First, you must authenticate yourself with Google to use the new subdomain.

They become Google Search Console in order to confirm this subdomain. If the domain has been confirmed on one of the variants offered there (I recommend the variant with the Entry in the DNS of your domainbecause you have to make further entries there straight away), you will return to the Google Cloud.

This authentication method also leads to a first entry in the DNS of the subdomain, a TXT entry. This has a value like:

google-site-verification=2ZKc6zIO......RcjzU

You should then see this new subdomain (possibly only after clicking on "Update domains") selectable in the drop-down list. After selecting the subdomain, you will receive the other necessary entries for the Domain Name System (DNS) of your domain.