Server Side Tracking – What’s Old is New Again

Introduction: The Importance of Data Collection

When we work with our clients on data and analytics; we strongly believe that the process of data collection is fundamental. Data quality should be the highest priority, and this can only be achieved through a robust and efficient workflow.

It might seem obvious, but if you’re not collecting the highest quality data, then your data will be of limited utility.  The results will never deliver the value-generating insights and information needed across your organisation; or as we like to say – garbage in, garbage out.

At Poplin, we always approach data collection as an evolving process. The further along the maturity curve you are, the better positioned you are to understand the importance of the various data sources and the more detailed and sophisticated your data models and use cases become.

As part of the data collection process, we strongly encourage everyone to consider server-side tracking, and the role it could play in your wider data collection strategy. 

We’ll get to those reasons in more detail, but first, it’s important to understand the current trend of client-side tracking, the key differences to server-side, and the pros and cons of both, particularly with the growing presence of ad blockers and ITP.


What is Client-Side Tracking

Client-side tracking is the most common set up for data collection. At its most basic, client-side involves the collection of data from the user’s browser and sending to a server – most commonly through tag management

Tag managers such as Google Tag Manager (GTM) are most commonly used to provide data for marketing purposes such as retargeting, as well as analytics and conversion tracking. This data involves user information that can be gathered from the client, such as client-side set cookies (often used for managing shopping carts on e-commerce sites), ad campaigns, and device information (which can sometimes be more important than you think… but we’ll get to that!)


Pros of client side tracking include:

  • Easy to set up and allows flexibility in deployment
  • Easier to test
  • Provides rich behavioural data
  • Visibility and transparency
  • Low barrier to entry via templates, pixels or small amounts of Javascript



  • Control is in the user’s hands, creating unknown variables
  • Can hinder page performance
  • Adblockers and ITP (Intelligent Tracking Protection)
  • Not everything happens on the client-side 
  • Any data you don’t want to expose client-side from a security perspective can’t be tracked on the client-side.


The considerations for Server-Side Tracking

While client-side tracking will continue to be the most common way for businesses to collect data, at Poplin we are always discussing when to consider the use cases for server-side tracking, and what additional value this richer data can drive to the business.

In a nutshell, server-side tracking is when the server makes a direct request to a destination endpoint (such as Snowplow or Google Analytics) rather than the client’s browser being responsible for making that request.  This process happens without the need to send a response back to the website mitigating any impact on the user browsing the website.

There are a number of reasons why teams might consider implementing server side tracking, the most obvious being the fact that some data is only available on the server. Consider an auction site where user A places a maximum bid of $50 on an item currently at $30. User B in browser places a bid of $35, this triggers a bid event for User A to increase their current bid from $30 to $35.  This data wouldn’t be available in the browser, so must be tracked serverside.

A prime example of this would be more accurate purchase data. Of course, it is common for companies to calculate purchase volumes from their transactional database. However, for customer journey analysis, and understanding behavioural drivers of conversion, it is nice to have these purchase events collected and structured in the same way as the client side behavioural events. As the purchase event can be considered mission critical, and may affect the way you want to subsequently segment or retarget your customers, it makes sense to track this on the server side. When it comes to tracking purchases on the client-side, for example, a number of factors can lead to inaccurate data including browser types and user behaviours; some research suggests that there can be up to a 30% error in the data. Missing data might include requests that are ad blocked, as well as a user closing their browser before the analytics request has been sent to the tracking system.

An additional example would be with an eCommerce business, there may very well be important contextual information to collect that the company doesn’t Back strength exercise: back and trapezius exercises bodybuilding for women: misconceptions! – self-confidence, spirituality & entrepreneurship. want to expose on the client side for financially sensitive reasons. Say with every add to cart event, it is interesting to add the current stock level, or with dynamic discounting you would like to track the profit margin – it is likely that neither of these commercially sensitive data points should be exposed on the client-side.

Server-side tracking also allows you to mitigate the impact of ad blockers and other client-side behaviours that cause inaccuracies. We’ll come to that in some more detail.


Pros of server side tracking

  • Is not affected by browser types/versions and other variables that can occur on the client-side including ad blockers
  • Security: allows the ability to track sensitive data without exposing to the client e.g., lifetime value
  • May improve  speed, especially in circumstances where there are a large number of clients
  • No front end release is required
  • Provide IP and geolocation
  • Complimentary personal information such as user history and previous purchase/order history



  • Often requires developer time to instrument
  • Many behaviours aren’t accessible client-side such as scrolling and click behaviour
  • Can result in difficulties tracking single page apps (SPAs) or progress web applications (PWAs) that have minimal communication with a server


Using Server Side Tracking for your ITP and Ad Blocker Strategy

As user privacy and ad blockers continue to evolve, one of the most asked questions from our clients is how they should look to approach data collection – often this involves from moving from third party data collection to first party data collection.

For us, server-side tracking is the best approach for those clients looking to have more control over the data they collect with the advent of ITP and ad blockers.

ITP (Intelligent Tracking Prevention) and ad / privacy blockers both deliberately target the capture of third party analytics and advertising data on the client-side. For end users it is often unclear as to where their data is being set and how it is being used. First party tracking – in which you run and control your own data collection and can seek consent from the user is the likely way of the future. 


The Poplin Data View

At Poplin, we strongly believe that focusing on the best quality data collection is the foundation for getting the best value out of your data. When it comes to how you collect data; this means considering both client-side and server-side tracking as a complementary strategy.

Using server-side tracking, such as that available with Snowplow, will put you on the path to greater data quality and set you up with the information you need to succeed. Snowplow provides a suite of official SDKs with a library of server side trackers, you can maintain the same interface for consistency, ease of portability and implementation. 

It all comes down to data quality. You want the best quality data available, providing you with the greatest insights and ability to use data to make decisions and provide your business with every possible advantage. 


Published by Mike Robins

CTO at Poplin Data

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