Client-side vs server-side tagging¶
Historically, websites primarily executed tags on the client side, meaning directly on the user's device. This approach was largely due to the high cost and limited availability of servers at the time.
This method of client-side tagging, however, creates significant challenges regarding * privacy. Implementing tags as described above typically requires integrating tracking code provided directly by third-party tool vendors* such as Google Analytics, Facebook, and other marketing platforms.
If tool vendors provide the code, website owners have limited ability to restrict what data the code collects and how the tool stores it.
Consequently, the core of the privacy dilemma lies in two fundamental principles: transparency and control:
- User control problem: If website owners have no control over the data collected by third-party tags, they cannot offer the same level of control to their users.
- Transparency problem: Tool vendors can sometimes be opaque about the actual data they collect, for example by creating digital fingerprints, which further undermines user trust and understanding.
Server-side tagging directly addresses both privacy concerns.
With server-side tagging, a central server, rather than the user's device, executes the tags that share data with third-party tool vendors. This central server gives website operators * full control* over what data they share with specific tool vendors and under what circumstances.
Server-side tagging with Delta.BG¶
The simplest and most effective method for getting started with server-side tagging is through Delta.BG Server-Side Tagging. This solution offers a fully managed hosting environment for Server-Side Google Tag Manager (GTM), eliminating the complexities typically associated with self-hosting.
Delta.BG Server-Side Tagging simultaneously addresses two key challenges when working with a tagging server:
1. Server management¶
It completely eliminates the need for organizations to manage and maintain their own servers. This includes concerns about server availability (uptime), performance optimization, security updates, and scalability. By taking on these operational burdens, Delta.BG allows businesses to focus on their core activities rather than infrastructure management.
2. Using Google Tag Manager¶
On the other hand, the solution leverages the power of Google Tag Manager (GTM), which is the most widely adopted and recognized solution for managing tags on websites and applications. Using GTM as the "operating system" for your server-side tagging brings several significant advantages:
- Near-universal adoption: GTM is widely used by analysts and marketers around the world, ensuring * familiarity and ease of collaboration* within marketing and analytics teams.
- Consistent principles: It operates on the same core principles as other types of GTM implementations (e.g., Web GTM), making the transition to server-side tagging smoother for those already familiar with the platform.
- Extensive template gallery: GTM features a vast and continuously growing gallery of pre-built templates. These templates, provided by Google and a large community of third-party developers, cover a huge range of use cases — from basic analytics tracking to advanced conversion measurement and advertising integrations. This rich resource significantly accelerates implementation and reduces the need for writing custom code.
How Delta.BG Server-Side Tagging improves user privacy¶
Due to the nature of client-side tagging, every tag executed on the client side will always communicate all HTTP headers and cookies to the receiving server — even if this is unintentional or unnecessary for the tool's purposes (Flow 1 below).
Instead, server-side tagging allows organizations to share only the essential data with tool vendors, preventing unnecessary over-sharing (Flow 2 below).
Consequently, Delta.BG Server-Side Tagging offers a significant privacy advantage, as it enables data processing that is truly purpose-limited (purpose-limited data processing).
In practice, this privacy improvement primarily takes the following two forms:
Data cleansing per tool¶
Before interaction data is sent to a specific tool (e.g., an analytics platform, an advertising network), server-side processes can be configured to identify personally identifiable information such as email addresses, as well as the data itself, and protect it from being shared.
This ensures that sensitive personal identifiers are removed or anonymized, preventing them from being shared with third parties when this is not permitted or necessary, while still sharing * valuable data* with the tool.
Preventing unintentional fingerprinting (Fingerprint-ability)¶
Digital fingerprints often rely on HTTP headers such as User-Agent, IP address, or other device traces.
Unlike a client-side tagging setup, a server-side tagging setup does not share such HTTP headers with third parties by default.
In this way, organizations can actively prevent the creation of digital fingerprints that could uniquely identify users without their knowledge.
Advantages of server-side tagging for advertisers and analysts¶
Beyond the privacy benefits, there are also advantages from a business perspective.
For example, it enables server-side integration of multiple vendors based on a single request coming from the user's device. This consolidation leads to a cleaner and more resilient tagging setup where all integrated tools benefit from a consistent and high-quality data stream.
This consistency is crucial for minimizing discrepancies between events reported across different platforms (e.g., page view events sent to Facebook versus those sent to Google Analytics). This ensures a unified and accurate understanding of user behavior across all marketing and analytics tools.
Unique capabilities for data collection and analysis¶
Additionally, server-side tagging provides unique capabilities for data collection and analysis:
1. Anonymous data collection¶
Even when personal data is not available due to the user's consent choice, server-side tagging enables the collection of valuable anonymous insights about website usage. This capability is vital for understanding aggregate user behavior without compromising privacy. Examples include:
- Consent banner usage insights: Observing how users interact with the consent banner — whether they accept, reject, or ignore it — can provide critical information for optimizing consent management strategies and improving the user experience.
- Evaluating ad campaigns with non-consenting users: By observing the behavior of users who do not interact with the consent banner at all, businesses can identify potential sources of low-quality traffic from advertising campaigns. This allows for more precise campaign optimization, reducing the waste of advertising budget on irrelevant or disengaged audiences.
2. Integrating sensitive data without user exposure¶
Server-side tagging facilitates the secure integration of highly sensitive business data without exposing it directly to the user's browser or publicly accessible systems. This opens new paths for advanced analytics and advertising optimization:
- Optimization with high-value signals: Key business metrics such as product margins, customer lifetime value (CLV), and conversion probability can be securely attached to events. This allows advertising campaigns to be optimized against these high-value signals, leading to * more impactful results compared to relying on "noisy" or less indicative signals such as transaction counts or raw revenue. By feeding these richer and more meaningful data into advertising algorithms, businesses can achieve a deeper understanding of campaign effectiveness and generate more profitable results*.