Mastering GTM: Extract & Consolidate Click IDs, Query Parameters & Cookies for Advanced Tracking

Google Tag Manager (GTM) offers unparalleled flexibility when it comes to tracking user interactions, extracting valuable data, and consolidating information like Click IDs, query parameters, and cookies for advanced analytics and attribution workflows.

Why Extract Click IDs, Query Parameters, and Cookies?

1. Click IDs: Platforms like Google Ads, Facebook Ads, and LinkedIn Ads append unique Click IDs (e.g., gclid, fbclid, li_fat_id) to URLs to track campaign performance and user attribution.
2. Query Parameters: Custom UTM parameters and other query strings in URLs provide critical marketing insights about traffic sources, campaigns, and keywords.
3. Cookies: Cookies store user behavior and session data, allowing persistent tracking across sessions or pages.

Consolidating this data into a structured format enhances attribution models, improves data analysis, and simplifies integration with tools like Google Analytics 4 (GA4), Amplitude, or your CRM.

Step 1: Set Up Variables in GTM

1. Extracting Query Parameters

Query parameters are accessible in GTM through URL Variables. Follow these steps:

1. Navigate to Variables > Configure > New.
2. Select URL Variable.
3. Set the Component Type to "Query."
4. Input the query parameter key (e.g., gclid, utm_source, or fbclid).
5. Name the variable appropriately (e.g., Query - gclid).

2. Extracting Cookies

To extract cookies, create First-Party Cookie Variables:

1. Go to Variables > Configure > New.
2. Select First-Party Cookie Variable.
3. Enter the cookie name you want to track (e.g., user_id, session_id).
4. Name the variable (e.g., Cookie - user_id).

3. Extracting Click IDs

Most Click IDs come as query parameters. Repeat the query parameter steps for each platform-specific Click ID:

• Google Ads: gclid
• Facebook Ads: fbclid
• LinkedIn Ads: li_fat_id

Step 2: Consolidate Data in GTM

To consolidate extracted values, use Custom JavaScript Variables or send the data to a single data layer object.

Option 1: Custom JavaScript Variable

1. Go to Variables > New > Custom JavaScript Variable.
2. Use the following example script to consolidate query parameters and cookies:

function() {
  var data = {
    gclid: {{Query - gclid}},
    fbclid: {{Query - fbclid}},
    li_fat_id: {{Query - li_fat_id}},
    utm_source: {{Query - utm_source}},
    utm_medium: {{Query - utm_medium}},
    user_id: {{Cookie - user_id}},
    session_id: {{Cookie - session_id}}
  };

  return JSON.stringify(data);
}        

1. Name the variable (e.g., Consolidated Data).
2. This variable can now be sent to your analytics or CRM tool as a unified object.

Option 2: Populate the Data Layer

Add a tag to push data into the Data Layer:

1. Go to Tags > New > Tag Configuration.
2. Select Custom HTML Tag.
3. Use the following script:

<script>
  window.dataLayer = window.dataLayer || [];
  dataLayer.push({
    'gclid': {{Query - gclid}},
    'fbclid': {{Query - fbclid}},
    'li_fat_id': {{Query - li_fat_id}},
    'utm_source': {{Query - utm_source}},
    'utm_medium': {{Query - utm_medium}},
    'user_id': {{Cookie - user_id}},
    'session_id': {{Cookie - session_id}}
  });
</script>        

1. Trigger the tag on all pages to ensure comprehensive data collection.

Step 3: Send Consolidated Data to GA4 or Other Tools

1. Sending Data to GA4

Use a GA4 Event Tag to send the consolidated data:

1. Go to Tags > New > GA4 Event Tag.
2. Select your GA4 Configuration Tag.
3. Set the Event Name to something meaningful (e.g., user_data).
4. In the Event Parameters section, map your variables:
5. Configure a trigger for the desired pages.

2. Sending Data to Other Platforms

For tools like Amplitude or Mixpanel:

1. Use a Custom HTML Tag.
2. Include the consolidated object in your platform’s JavaScript API (e.g., amplitude.logEvent or mixpanel.track).

Example:

<script>
  amplitude.getInstance().logEvent('User Data', {
    gclid: {{Query - gclid}},
    fbclid: {{Query - fbclid}},
    utm_source: {{Query - utm_source}},
    user_id: {{Cookie - user_id}}
  });
</script>        

Best Practices

1. Validation: Use GTM’s preview mode to validate that variables and tags are capturing the correct data.
2. Data Retention: Ensure compliance with privacy regulations like GDPR/CCPA. Avoid storing personal identifiers unless properly anonymized.
3. Custom Parameters: If you’re running campaigns with unique parameters, add them to your GTM setup proactively.
4. Documentation: Keep a detailed record of all variables, tags, and triggers for future maintenance.

Conclusion

Extracting and consolidating Click IDs, query parameters, and cookies using GTM allows marketers and analysts to optimize attribution and reporting workflows seamlessly. By setting up structured variables and leveraging the data layer or JavaScript, you can unify disparate data sources for enhanced analysis and better decision-making. Start implementing these steps today to unlock the full potential of GTM and your analytics stack!

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