Guide to Google First Party Mode

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Introduction to Google First-Party Mode.

First Party Mode allows websites to serve tracking scripts from their domain instead of relying on Google’s servers.

Advantages of using Google First-Party Mode.

The following are the key advantages of using First Party Mode:

It improves conversion tracking by making data collection more resilient to browser restrictions and ad blockers.
It improves tracking reliability by preventing third-party script loading issues.
Minimises tracking disruptions caused by browser restrictions and ad blockers.
Enhances privacy compliance by keeping data within a first-party context.
Simplifies setup for websites using a compatible CDN (Content Delivery Network) since no changes to GTM tag code are required.

Here is how the First Party Mode Works.

Let’s say you run an e-commerce website (example.com) and want to deploy Google Tag in First-Party Mode.

Instead of Google Tag loading from Google’s servers (https://www.googletagmanager.com), you configure it to load from your own domain, such as: https://example.com/tag/

To set this up, you need to configure your Content Delivery Network (CDN), load balancer or proxy to handle and forward these requests to this subfolder (‘/tag/’).

You don’t need to set up server-side tagging or a server container for First-Party Mode.

For example, your CDN (like Cloudflare) is configured to listen for incoming tag requests at https://example.com/tag/ and forward them to Google’s servers.

Normally, Google Tag (gtag.js) loads from:

https://www.googletagmanager.com/gtag/js?id=G-XXXXX

In First-Party Mode, the script appears to load from your own domain:

https://example.com/tag/gtag/js?id=G-XXXXX

However, you don’t actually need to modify the script on your pages if your CDN supports automated URL rewrites. The CDN will handle the redirection transparently.

This ensures that Google Tag now loads as if it’s part of your own website, making it somewhat harder for ad blockers to detect and block tracking.

However, advanced ad blockers may still be able to identify and block known tracking paths.

First-Party Mode improves privacy by keeping requests within a first-party context and can help with some browser restrictions. Still, it doesn’t provide the same level of data control or ad blocker resistance as full server-side tagging.

Note: First-Party Mode may affect how the tags interact with on-page consent settings, so additional testing is recommended.

First-Party Mode vs. Server-Side Tagging.

#1 First Party Mode routes requests through a subfolder on the website (e.g., /tag/), while Server-Side Tagging (Server-Side Tagging) uses a dedicated tagging server (e.g., Server-Side Tagging.example.com).

#2 First Party Mode reduces the likelihood of blocking but remains detectable, whereas Server-Side Tagging is much more resistant since tracking occurs server-side and remains invisible to the browser.

#3 First Party Mode provides limited data control, as it only forwards requests to Google, meaning you can’t modify, filter, or anonymise data before sending it. Whereas, Server-Side Tagging gives you full control over data processing, allowing you to modify, strip, or enrich data before forwarding it to Google or other platforms (e.g., Meta, TikTok).

#4 First Party Mode only works with Google products (GA4, Google Ads). Whereas, Server-Side Tagging supports both Google and Non-Google products.

#5 Server-Side Tagging provides better privacy compliance (GDPR, CCPA) than First Party Mode since data can be processed, modified, or restricted before being sent.

#6 First Party Mode is easy to implement if the website uses a compatible CDN, while Server-Side Tagging requires a dedicated server setup, making it more complex.

Should you be using both First Party Mode and Server-Side Tagging, or does Server-Side Tagging already cover First Party Mode?

You do not need to use both First Party Mode and Server-Side Tagging together because Server-Side Tagging already provides the benefits of First Party Mode and more.

When correctly configured, Server-Side Tagging already loads Google scripts (gtm.js, gtag.js) through your own server, just like First Party Mode.

This means you don’t need First Party Mode to achieve a first-party tracking setup because Server-Side Tagging can already serve scripts from your domain.

When would you use First Party Mode instead of Server-Side Tagging?

Use First Party Mode only when you want an easy, no-code way to enable first-party tracking for Google products without setting up and maintaining a dedicated server for Server-Side Tagging.

First Party Mode is a poor replacement for Server-Side Tagging.

>> First Party Mode reduces the likelihood of blocking but remains detectable, whereas Server-Side Tagging is much more resistant since tracking occurs server-side and remains invisible to the browser.

>> First Party Mode provides limited data control, as it only forwards requests to Google, meaning you can’t modify, filter, or anonymise data before sending it. Whereas, Server-Side Tagging gives you full control over data processing, allowing you to modify, strip, or enrich data before forwarding it to Google or other platforms (e.g., Meta, TikTok).

>> First Party Mode only works with Google products (GA4, Google Ads). Whereas, Server-Side Tagging supports both Google and Non-Google products.

>> Server-Side Tagging provides better privacy compliance (GDPR, CCPA) than First Party Mode since data can be processed, modified, or restricted before being sent.