Skip to main content

Integrate Seers’ Server-Side Tagging with Meta

Updated

This guide provides a step-by-step approach to setting up Meta Pixel and the Meta Conversions API (CAPI) using Google Tag Manager (GTM) and a server-side container. This "parallel tracking" method is the most robust way to ensure accurate and resilient data collection for your Meta advertising campaigns.    

Prerequisites  

Before getting started, make sure the following are in place:

  • Meta Business Suite: Access to your Meta Business account, including the Events Manager for your specific Pixel. You will also need this for testing events.
  • Pixel ID and Access Token: Required for sending Conversions API events. Both can be obtained from your Meta Events Manager. Refer to Meta's documentation for instructions on retrieving your Pixel ID and generating an access token.
  • Web Google Tag Manager (GTM): A web GTM container already deployed on your website, configured to send GA4 events to your server-side GTM instance. Refer to Google's documentation on sharing GTM container access.
  • Server-Side GTM Container (Seers): A server-side GTM container provisioned by Seers, accessible through a first-party endpoint, and set up to process GA4 events. Visit the Seers Get Started guide to configure your server-side GTM, and refer to the GTM documentation for sharing container access.

Why Use Server-Side Tagging for Meta?

Greater Data Accuracy

Server-side tagging sends data through your own server rather than the user's browser, bypassing ad blockers and browser-level privacy restrictions such as Safari's ITP or Firefox's ETP. The result is more complete and dependable conversion data reaching Meta.

Stronger Data Control

You decide precisely what information is shared with Meta. This gives you the flexibility to enrich, filter, or anonymise data to stay compliant with regulations like GDPR and CCPA. Moving tagging server-side also reduces the JavaScript load in the browser, helping improve page speed, Core Web Vitals, and potentially your SEO performance.

Extended Attribution Windows

Because cookies are set from your own domain rather than a third-party domain, their lifespan is significantly extended in browsers such as Safari. This leads to better long-term attribution and a more complete picture of your campaign performance.

Implementation Overview

This setup follows a parallel tracking model. Events are sent from two sources simultaneously: the user's browser via Meta Pixel, and your server via the Conversions API. Meta uses a unique Event ID to deduplicate these signals, ensuring that each user action is counted only once, regardless of which source reported it first.

Seers_server_Ai_GTM.png

Step 1: Parallel Tracking Implementation

Part A: Web GTM Configuration (Client-Side)

  •  Open your server-side GTM container and navigate to Tags, then click New.
  • From the list of available built-in tag types, select Conversion Linker.
Note: The Meta CAPI template in the server container is compatible with Google Analytics events forwarded from the web container. The steps below assume Google Analytics is being fired from the web GTM container.

Create a Unique Event ID Variable

Deduplication requires every event to carry a unique ID that is identical across both the browser and server events for the same user action.

  1. In your Web GTM container, go to Variables and click New.

  2. Select Custom JavaScript Variable and paste in the following code:

```
function() {
  var timestamp = new Date().getTime();
  var randomNumber = Math.random().toString(36).substring(2);
  return 'evt_' + timestamp + '_' + randomNumber;
}
```
  1. Name this variable CJS - Unique Event ID. 

Add the Event ID to Your GA4 Event Tags

On each GA4 event tag in your web container, add a parameter named event_id and set its value to the {{CJS - Unique Event ID}} variable.

Set Up the Meta Pixel Tag

1.    In your Web GTM container, go to Tags and click New.

2.    Click Tag Configuration and search for the Facebook Pixel tag template by Facebookarchive in the Community Template Gallery.

3.    Enter your Meta Pixel ID. It is best practice to store this value in a Constant variable for easy reuse.

4.    For the PageView event, and any other standard or custom events, expand the More Settings section and insert the {{CJS - Unique Event ID}} variable in the Event ID field.

5.    Set the trigger to All Pages for the base PageView tag. For other events, such as add_to_cart or purchase, apply the appropriate event-specific triggers.

Important: The triggers used for your Meta Pixel tags must match exactly the triggers used for your corresponding Google Analytics tags. This ensures the same Event ID is shared between the browser event and the server event.

Part B: Server-Side GTM Configuration

With the web container configured, the next step is to set up the server container to receive the incoming data and forward it to Meta's Conversions API.

Set Up the Meta Conversions API Tag

In your server-side GTM container, navigate to Templates and click Search Gallery. Search for "Seers" and select the Meta Conversion API Tag by Seers template.

  1. Click Add to Workspace and confirm by clicking Add again.
  2. Go to Tags and click New. Click Tag Configuration and select the Seers Meta Conversion API template you just added.
  3. Configure the following fields: 
  •  Pixel ID: Enter the same Meta Pixel ID used in your web container.
  • API Access Token: In your Meta Events Manager, go to Settings and generate an access token under the Conversions API section. Store this securely as a variable in your server-side GTM container.
  • Action Source: Set this to Website.
  • Optionally, enable Extend Meta Pixel Cookies. When this is active, Facebook's cookies are set server-side, which significantly extends their lifespan compared to browser-set cookies.
  1.  If your web GTM container uses the standard GA4 e-commerce event naming convention, the tag template will automatically map incoming events to their Meta standard event equivalents.

Configure the Trigger

  • Set the trigger to fire on all events from your GA4 client. Create a new Custom trigger and configure it to fire when Client Name equals the name of your GA4 client.
  •  Ensure consent is validated at the trigger level. Follow the Seers' consent guidelines when configuring this. 
  • Consider allowlisting only the specific events you want to forward to Meta, both standard and custom. This reduces noise in your analytics and limits the volume of data shared with third-party vendors.

Step 2: Quality Assurance

Testing is an essential part of this setup. Use server-side GTM's Preview mode together with Meta's Test Events tool to validate your implementation before going live.

Part A: Validation and Debugging

Debugging Before Go-Live

Before publishing any changes, verify that both your browser-based and server-based events are working as expected by following these steps:

  1. Open Preview Mode in both your Web GTM and server-side GTM containers.
  2. In your Meta Events Manager, open the Test Events tab.
  3. Load your website from the GTM Preview tab and navigate around to trigger the events you have configured.
  4. In the Web GTM Preview, confirm that your Meta Pixel tags are firing. Click on a tag and check the Event ID being sent.
  5. In the server-side GTM Preview, verify that incoming requests from your GA4 client are appearing. Click on the Meta Conversions API tag that fired and inspect the Event ID in the outgoing request to Meta; it must be identical to the Event ID from the web GTM tag.

  6. In the Meta Events Manager Test Events tab, confirm that events are arriving. For each event name, you should see one event originating from the server and one from the browser, both sharing the same Event ID. Matching Event IDs is what allows Meta to deduplicate correctly. Refer to Meta's deduplication documentation for further details.

    Datasets.png

Quality Checks After Go-Live

Once your setup is live, perform regular checks in your Meta Events Manager (under the overview section for your Pixel ID) to confirm all events are reporting as expected. For each event, the volume of server-based events should be equal to or greater than browser-based events, and server-side tracking should outperform client-side due to its resilience against blockers.

If you notice discrepancies, click View Details on the relevant event. Meta will surface additional information about what data may be missing from your server events, helping you diagnose and resolve the issue.

View_content.png

Part B: Common Challenges and Solutions

Challenge: Events Are Not Being Deduplicated

Solution: The most common cause is a mismatch in the event_id value. Use Preview mode in both containers to confirm that the exact same event_id is being sent from both the browser and the server for the same user action. Also, verify that the event names are identical on both sides (e.g., add_to_cart in the browser must match add_to_cart on the server).

Challenge: Low Event Match Quality (EMQ) Score

Solution: The EMQ score reflects how effectively Meta can match an event to a user profile. To improve it, send more user-identifying parameters. The most valuable are: hashed email (em), phone number (ph), first name (fn), last name (ln), and the fbp (Facebook browser ID) and fbc (Facebook click ID) cookie values. Check that your server-side GTM tag is configured to capture and forward all of these, where available.

Challenge: Server Events Not Appearing in Meta

Solution: Open the server-side GTM Preview mode and check the Tags tab to confirm whether the CAPI tag fired. If it shows as failed, navigate to the Outgoing HTTP Requests section and open the Response tab. This will typically contain an error message from Meta explaining why the event was rejected, which will point you toward the fix.

Step 3: Final Optimisations (Optional but Recommended)

Improve Event Match Quality

Conduct a systematic review of your data layer and the user information available across your site. Work with your development team to surface additional data points, both non-PII and hashed PII, that can be passed through the Conversions API. The richer and more accurate the data you provide, the more effective your ad targeting and attribution will be.

Reduce Redundant Browser-Side Tracking

Once you are confident in the reliability of your server-side setup, you can consider suppressing certain Meta Pixel tags from firing in the browser for specific users or scenarios, for example, for logged-in users where comprehensive server-side data is already available. This can further improve site performance by reducing client-side JavaScript execution. This is an advanced step and should be approached carefully to avoid unintended gaps in tracking.  


 

Related articles

Powered by Zendesk