What is Server-side Tagging?

What is Server-side Tagging?

As web tracking and analytics have evolved, so too have the methods for delivering and managing the tags that collect user data. Traditionally, most organizations have relied on client-side tagging, where tracking scripts run directly in the user’s browser. While this approach has worked for years, it now faces significant challenges:

• Privacy regulations like GDPR and ePrivacy Directive demand stricter data handling.
• Browser restrictions (e.g., Safari’s Intelligent Tracking Prevention, Firefox’s Enhanced Tracking Protection) block or limit third-party cookies and scripts.
• Ad blockers and privacy tools disable many client-side tags altogether.
• Performance concerns arise as complex tracking scripts increase page load times and hurt user experience.

Server-side tagging offers an alternative. By moving tag execution from the browser to a server you control, it allows marketers and developers to:

• Filter, enrich, and route data before it reaches third-party vendors.
• Improve site performance by reducing client-side JavaScript execution.
• Maintain more robust analytics in a world of increasing signal loss.

In this article, we explore what server-side tagging is, how it works, its benefits and limitations, different deployment approaches, and real-world use cases where this technology is making an impact.

The Basics: How it works

At its core, server-side tagging shifts the execution of tracking tags from the user’s browser (client-side) to a server that you control. This change fundamentally alters how data is collected and transmitted to analytics and advertising platforms.

Client-side vs Server-side Tagging

In a client-side setup, the user’s browser downloads and runs multiple third-party scripts directly on each page load. These scripts send data about user interactions (page views, clicks, form submissions, etc.) to external vendors like Google Analytics, Facebook, or advertising networks.

By contrast, server-side tagging introduces an intermediary step:

• A lightweight client-side collector sends raw interaction data (e.g., pageviews, events) to a server you manage.
• The server processes, filters, and enriches the data.
• Only then does it forward the relevant information to third-party services.

This allows organizations to keep more control over what data leaves their domain and in what form.

Core components of Server-side Tagging

A typical server-side tagging setup involves:

• Client collector: A browser-based snippet that sends user interaction data to your server. Traffic can be routed through a first-party domain to ensure data is collected in a first-party context, reducing the impact of browser restrictions such as Intelligent Tracking Prevention (ITP).
• Server container: A server environment that processes incoming data, applies business logic, and triggers the appropriate tags.
• Tags, triggers, variables: Configurations within the server container that define what data is sent where.

Deployment environments

Server containers are usually hosted in cloud environments such as:

• Google Cloud Platform (App Engine, Cloud Run)
• Amazon Web Services (Elastic Container Service)
• Self-hosted solutions for organizations with strict data sovereignty requirements.

By hosting in the cloud, businesses can scale processing power based on traffic and maintain low latency for tag execution.

Key benefits

More performance and better user experience

One of the most immediate advantages of server-side tagging is the impact on website performance and user experience. By moving the heavy lifting of tag execution from the browser to a server, websites can reduce the amount of JavaScript running on the client side. This results in faster page load times and improved Core Web Vitals metrics, both of which are increasingly important for SEO and user retention. Visitors encounter fewer delays, leading to smoother navigation and higher engagement. 

Focus on data protection and control

Beyond performance, server-side tagging offers marketers and developers far greater control over their data. In traditional client-side setups, third-party vendors often receive raw, unfiltered user data directly from the browser. With server-side tagging, organizations can pre-process and sanitize this data before forwarding it. This means they can enforce stricter privacy rules, anonymize sensitive fields, and ensure that only necessary information is shared with analytics and advertising platforms. It also allows the creation of first-party cookies that are less susceptible to browser restrictions, a critical advantage in the age of Intelligent Tracking Prevention (ITP) and similar technologies. Read in our blog article, how you can overcome Safari’s ITP.

Resilience against ad and tracking blocker

Another significant benefit lies in the resilience to ad blockers and privacy tools. Since the data flows to a first-party server under the organization’s domain, it becomes harder for browser-based blocking tools to detect and interrupt tracking requests. This helps maintain more accurate analytics and attribution even in environments where client-side tracking fails.

Ethical aspects and transparency

At the same time, it is important to acknowledge the ethical considerations often raised in this context. While server-side tagging makes it technically possible to recover traffic and data otherwise blocked by ad blockers, it also provides organizations with the ability to respect user choices. A server-side setup allows for clear, transparent handling of such decisions—enabling configurations that can honor the use of ad blockers and make these practices publicly visible if desired.

Deployment approaches

Server-side tagging is not a one-size-fits-all solution. Organizations can choose from different approaches depending on their technical resources, data governance requirements, and marketing needs.

One approach is a hybrid model, where a lightweight client-side collector still sends data from the browser, but instead of directing it straight to multiple third-party services, it forwards it to a server-side container. This container acts as a central hub, processing the incoming data and then distributing it to external vendors. The advantage of this setup is that it retains some of the flexibility of client-side tracking while gaining control and privacy benefits from server-side processing. It also requires less drastic changes to existing workflows, making it a practical first step for teams transitioning away from fully client-side architectures.

JENTIS hybrid approach

JENTIS is an example of this hybrid approach. Its technology enables organizations to separate data collection from data delivery by running a server-side container in parallel with a client-side tag manager. This setup allows businesses to maintain control over their data flows, apply privacy rules, and enrich datasets before sending them on to analytics or marketing platforms. Because JENTIS processes data within a server environment under the organization’s domain, it also helps mitigate the impact of browser tracking restrictions and ad blockers.

Full server-side tracking

For organizations seeking maximum control, a pure server-side tracking approach is also possible. In this setup, data is sent directly from the organization’s own servers to analytics and marketing platforms via API calls, bypassing the browser entirely.

This model is particularly appealing for businesses in highly regulated industries, where data residency and strict compliance are critical. However, it also demands a higher level of technical sophistication and may require custom integrations for each vendor, as not all platforms are optimized for server-to-server communication. Additionally, handling consent decisions becomes more complex in this setup, and certain browser-based values, such as screen size, viewport dimensions, or other client-specific information, cannot be captured, as they are only accessible in the browser context. This blog article covers everything you need to know about server-side tracking.

Conclusion

Server-side tagging represents a significant evolution in how organizations collect and manage data for analytics and marketing. By shifting tag execution from the browser to a controlled server environment, it helps address growing concerns around privacy, browser restrictions, and website performance. While it introduces technical challenges and requires careful planning, hybrid models such as those offered by JENTIS show how businesses can take a pragmatic approach to adopting this technology.