Measurement and analytics in digital marketing have been undergoing significant changes in recent years. The restriction of cookies, increased emphasis on privacy protection, and various ad blockers mean that traditional "browser-based" measurements are no longer sufficient. This is where Server-side Google Tag Manager (GTM) comes into play.
How Client-Side GTM Works
Typically, GTM works by deploying its container onto a website, and all tags (e.g., Google Analytics, Meta Pixel, LinkedIn Insight Tag, etc.) are executed in the user's browser.
However, this brings several issues:
- Data loss due to ad blockers and cookie restrictions,
- Website slowdown when multiple scripts are loaded,
- Security risk because data goes directly through the browser.
What is Server-Side GTM
Server-side GTM shifts part of this process to your own server (or a server running in Google Cloud). Instead of the user's browser sending all data directly to third parties, it first sends it to a server container. This container processes, cleans, and then forwards the data – for example, to Google Analytics 4, Facebook, or other marketing tools.
Why It Matters
- More accurate data – less loss due to ad blockers or cookie expiration.
- Faster website – tags are not loaded directly in the browser, reducing load.
- Control over data – you decide which information to send and how.
- Better privacy compliance – you can better adhere to GDPR and other regulations because you process data on your own server.
- Possibility of advanced integrations – you can prepare your own data transformations, enrich them with internal data (e.g., CRM), and send more personalized events.
When to Switch to Server-Side GTM
- If data quality is crucial for you (e.g., e-commerce, SaaS, financial sector).
- If you use multiple marketing channels and need consistent, reliable data.
- If you want to prepare for a world with fewer cookies and stricter regulations.
What to Consider Before Deployment
Server-side GTM is not just about clicking "install." Before deployment, it's important to consider several factors to ensure successful and efficient implementation.
- Technical Preparation
- You will need a server (typically Google Cloud App Engine or another solution) and properly configured DNS records (e.g., a custom subdomain like gtm.yourdomain.com). These steps require technical know-how or collaboration with a partner experienced in this area.
- Thoughtful Data Model
- It's essential to have a clear idea of which data you want to collect, where you will send it, and why. A properly set data model is the foundation for obtaining quality and usable data.
- Operating Costs
- Unlike regular GTM, the server version is not free. Operating costs are associated with the Google Cloud project, primarily depending on the volume of data processed. For an average website, costs range in the tens of euros per month. However, these expenses should be seen as an investment that brings more accurate measurement and better campaign returns.
Server-side GTM is the next step in measurement evolution. It brings more accurate data, faster websites, and greater control over what and to whom you send. Yes, it requires a bit more preparation and technical knowledge, but the reward is modern measurement that gives you a competitive edge.
Uičkovský tip: Although implementing Server-side GTM requires initial preparation, the benefits of more accurate data, faster websites, and greater control over your data quickly pay off for large e-shops and companies. Want to find out if Server-side GTM is suitable for your business? Contact us. We will be happy to discuss deployment options with you and help you set up measurements to get the most out of your campaigns.
