Server-Side Google Tag Manager: An Overview

1. Introduction

Google Tag Manager (GTM) is a popular tool for managing tags and tracking codes on websites without the need to directly modify the source code. While traditional GTM operates on the client side, the server-side variant has emerged as a powerful extension. In this article, we will take a closer look at Server-side Google Tag Manager (sGTM), its features, as well as its advantages and disadvantages.

2. What is Server-Side Google Tag Manager?

Definition and Operation

Server-side Google Tag Manager is an extension of the classic GTM that allows tags and tracking codes to be executed on a server instead of on the client (browser). This means that the processing of tags occurs in a server-side environment, providing better control over data and its security. sGTM acts as an intermediary between the website and third-party services, with data being sent to the server first and then forwarded to the relevant services.

Differences from Client-Side Google Tag Manager

Unlike client-side GTM, where tags are executed in the user’s browser, sGTM operates on a server. This difference brings numerous advantages, particularly in the areas of data protection and performance. While client-side GTM potentially loads large amounts of data and scripts into the browser, sGTM can reduce the amount of data sent and better protect sensitive information.

3. How does Server-side Google Tag Manager work?

Technical Basics

Implementing Server-side Google Tag Manager requires setting up a server that acts as a tag gateway. This server receives tracking data from the website and processes it according to the rules configured in GTM. sGTM can be operated in a cloud environment like Google Cloud Platform or on a dedicated server.

Integration and Implementation of Server-side Google Tag Manager

To use sGTM, companies must set up a tag gateway server and host the relevant GTM containers there. The website then sends tracking data to this server, which reviews, filters, and forwards the data to the intended analytics and marketing platforms. This additional layer provides more control and allows for better optimization of tracking setups. sGTM often uses GA4 on the client side as a bridge to connect to other tools, which can potentially affect data quality. Although it offers a variety of community-developed APIs and templates, these can sometimes be inconsistent and require additional configuration.

4. Features of Server-side Google Tag Manager

Tag Management and Execution

Server-side Google Tag Manager allows centralized management and execution of tags on a server, offering more precise control and improved data security. Tags can be triggered by server-side scripts, reducing dependency on client-side factors such as browser compatibility and network speed. This can lead to improved page load times, as fewer resources are required on the client side.

Data Processing and Forwarding

A key feature of sGTM is its ability to filter and adjust incoming data before forwarding it to third-party services. This function allows only relevant and necessary data to be transmitted, increasing data security and reducing the volume of data sent to external services. Additionally, sensitive information can be anonymized or removed before leaving the server. This flexibility also supports DCP Tracking (Data Collection Point Tracking), enabling precise data collection and forwarding.

Advanced Tracking Capabilities

sGTM facilitates the integration of server-side data sources and enables companies to securely process sensitive information that cannot be handled by client-side GTM. This setup allows the creation of custom data models, adjustment of data collection, and tailoring of data processing to specific business requirements. Furthermore, sGTM supports advanced data enrichment by integrating additional contexts from internal databases or CRM systems, improving the depth and quality of analyses. However, it is important to note that a native connection to Firebase (Firestore, etc.) or other Google Cloud services is only possible if sGTM is hosted on Google Cloud.

5. Benefits of Server-side Google Tag Manager

Data Protection and Security

Since data processing takes place server-side, sGTM offers improved control over the collected information. Companies can better manage how data is collected and processed, making it easier to comply with data protection regulations such as GDPR. Sensitive data can be removed or anonymized before being passed on to third-party providers, reducing the risk of data breaches.

Performance Improvements and Load Times

By offloading tag execution to a server, the load on the browser is reduced. This results in faster page load times and a better user experience, as fewer resources are needed on the client side. This can significantly improve performance, especially on websites with high traffic or many tags.

6. Disadvantages of Server-side Google Tag Manager

Implementation Complexity

Implementing sGTM requires technical expertise and careful planning. Companies must set up and manage a dedicated server, which requires additional resources and knowledge. This can be particularly challenging for smaller companies that may not have the necessary technical resources.

Cost and Resource Requirements of Server-side Google Tag Manager

In addition to the complexity of implementation, costs can also be a barrier. Operating a dedicated server or using a cloud solution incurs ongoing costs, which may be higher than using client-side GTM. Regular maintenance and updates are also necessary to ensure the system’s security and performance.

Dependence on Technical Expertise

The use of sGTM requires a higher level of technical expertise compared to client-side GTM. Companies need IT professionals who are familiar with server management, network security, and programming. This dependency can limit flexibility, especially if internal resources are limited. Additionally, the implementation process can be more complex and time-consuming, as it involves setting up the server infrastructure, configuring secure data pipelines, and ensuring compliance with data protection regulations. The need for continuous monitoring and maintenance of the server environment also increases operational effort. Furthermore, troubleshooting may require deeper technical knowledge, which can be challenging for companies without a dedicated technical team.

Dependence on Community for Connectivity

Few in-house tools connect directly from Google; the rest must either be developed in-house or sourced from the community, which usually requires special customization. Additionally, reliance on third-party APIs for data forwarding can be maintenance-intensive and prone to disruptions.

Compliance Challenges

Under the Schrems II ruling, compliance with Google Tag Manager (GTM) and Google Analytics was extremely problematic due to concerns about data sovereignty. GDPR imposes strict regulations on the collection, storage, and transfer of personal data, and the use of services based in the U.S. posed significant risks, as this data is subject to U.S. laws such as the CLOUD Act. The Data Privacy Framework (DPF) has temporarily alleviated these concerns and established a new basis for data transfers between the EU and the U.S. However, uncertainty remains, as the European Court of Justice (ECJ) could overturn the DPF at any time, as it did with previous regulations such as Safe Harbor and Privacy Shield.

For companies looking to future-proof their operations, it is important to exercise caution when using Google services, as the risk of renewed legal changes leading to compliance challenges remains. Companies should therefore consider alternative solutions that offer greater data sovereignty and better long-term compliance security to minimize potential legal risks.

7. Comparison: Server-side vs. Client-Side GTM

Direct Comparison of Pros and Cons

Client-Side GTM is easier to implement and requires less technical expertise. It allows tracking tags to be executed directly in the user’s browser, enabling quick setup and easy adjustments. However, this can lead to longer load times and compromise data security, as data is sent directly to third-party providers.

Server-side GTM, on the other hand, offers greater control over data processing and improved data security. Tags are executed on a server, which improves browser performance and allows for data filtering before transmission. However, this solution requires more complex implementation and higher costs to operate a server.

While Client-Side GTM is ideal for simple and quick implementations, Server-side GTM is suitable for companies that place a high value on data protection and performance and have the technical resources to handle the implementation. For further information on the differences between server-side and client-side tracking, read our blog article.

8. Comparison: Server-side Google Tag Manager vs. JENTIS Server-side Tracking

Server-side Google Tag Manager and JENTIS Server-side Tracking both offer solutions for server-side tracking but differ in their architecture and features. sGTM is a solution from Google that is deeply integrated into the Google ecosystem, while JENTIS offers an independent platform focused on ensuring higher data quality while maintaining compliance with data protection regulations.

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