Improve your website & ad campaign performance with server-side GTM

Tracking and analysing user behaviour is a critical aspect of today’s digital landscape. However, traditional approaches to tracking are being crippled by legislative shifts in major markets including Europe and the US, as well as major tech companies such as Apple & Mozilla implementing changes which significantly undermine tracking capabilities.

Digital tools such as Google Tag Manager (GTM), Google Analytics (GA), and ad tracking pixels (Meta Pixel, TikTok Pixel, etc) are in widespread use across the open internet. You almost certainly have one or more on your website. These tools are quickly becoming severely impacted by shifts in digital privacy. 

Many websites currently utilise traditional browser-based Google Tag Manager. What many everyday users are unaware of is an advanced version called server-side Google Tag Manager, which can help to restore some of your conversion tracking and campaign performance.

Server-side GTM moves digital tracking tags from the client (website visitors’ browsers) to a server living on a subdomain of your website. The container loaded in the client browser still has tags and sends requests, but can have far less code and isn’t as affected by anti-tracking software.

In this post, we’ll briefly touch on the benefits of server-side GTM in the context of analytics and ad tracking technology.

Increased data privacy control

If you run advertising, you’ll almost certainly have ad tracking pixels (e.g. Meta, TikTok) installed on your website. 

These ad tracking pixels load third party JavaScript files on your webpages, which you as a website owner have no control over. For example, the Meta Pixel can – and does – scrape customers’ personal data from your website, unless a setting is switched off in the Meta Ads interface. 

Server-side GTM, on the other hand, captures and processes all data on your server before it is sent to any of those third parties. As a website owner, you have full control to dictate which advertising platforms receive what data. Your customers’ data is much more secure as a result.

Increased ad campaign optimisation

You spend thousands of dollars on digital advertising. Ad tracking is a must for measuring performance and optimising campaigns.

However, advertising platforms are losing their tracking capabilities. Third-party cookies are already blocked by Safari and Firefox. Chrome is set to follow suit by the end of 2024.

You’re likely seeing campaigns beginning to work less efficiently. Your conversion tracking is probably showing discrepancies. Most recently, Facebook Ads removed their Inspect Tool in January 2023. It is becoming clear that Meta’s ad platform is no longer able to report on many of its metrics with statistical significance.

In response, many advertising platforms are now allowing you to share your customers’ encrypted 1st party data with them in order to reinvigorate campaign performance. The ad platform can then match that data to any known users who have clicked on their ads. 

The Facebook Conversions API is perhaps the most well-known example of this. Anyone who clicks on a Meta ad will be logged into Facebook/Instagram. This means Meta has a rich trove of personal data about the people that click on their ads. 

When a conversion occurs on your website, you can share your customers’ user data (e.g. email, phone number) in an encrypted format to Meta via the Facebook Conversions API. If the data matches Facebook’s encrypted data of anyone who clicked/saw on one of your ads, that conversion can be successfully attributed to the ad click/view.

While there are many approaches to implementing the Facebook Conversions API, server-side GTM is one of the most robust and flexible methods.

Increased data accuracy

With client-side GTM, tracking code is executed in the user’s browser, which can be subject to restrictions such as ad blockers or browser tracking preventions. The latter is particularly prominent in Safari, which holds 29% market share throughout New Zealand.

Server-side GTM executes tracking code on your website server. For example, you’re on right now. Server-side GTM will send data to, a subdomain we’ve configured. 

Tracking prevention is much less likely to happen for requests to your own domain. This means that server-side GTM tracking is not subject to the same restrictions as browser-side GTM and is unaffected by browser performance. 

As a result, server-side GTM provides more reliable tracking and can reduce the likelihood of data loss or incorrect data capture.

Increased website speed

Traditional client-side GTM can cause website performance issues, particularly on slower devices or for larger organisations with heavy or complex websites.

With server-side GTM, you can migrate many tags to execute on your own server. The burden is removed from your users’ browsers, reducing load times and improving their website experience.

In summary

Server-side GTM is a powerful tool to improve your digital tracking infrastructure and restore visibility on what marketing is working. It offers many advantages that can help you take control of your data, speed up your website, and remain legally compliant as the privacy-conscious digital ecosystem continues rolling into an unknown future.