How to Use Google Tag Manager to Improve Website Speed and Performance

1. Audit and Remove Unnecessary Tags

A cluttered GTM container is a common cause of slow websites. Over time, as marketing campaigns come and go, it’s easy to accumulate outdated or redundant tags that no longer serve a purpose. 

How to Audit Your Tags: 

• Review All Tags: Go through each tag in your GTM container and ask if it’s still needed. Remove tags for old campaigns, expired promotions, or tools you no longer use. 

• Check for Duplicates: Sometimes, similar tags are added multiple times by different team members. Consolidate or remove duplicates. 

• Pause vs. Delete: If you’re unsure about a tag, consider pausing it first. This allows you to test the impact before permanent removal. 

Benefits: 

• Reduces the number of scripts loading on your site. 

• Minimizes the risk of conflicts or errors. 

• Makes your GTM container easier to manage and troubleshoot. 

Pro Tip: Schedule a quarterly or bi-annual tag audit as part of your website maintenance routine. 

2. Load Tags Selectively

Not every tag needs to fire on every page. Loading tags only where they are relevant can significantly improve performance. 

How to Load Tags Selectively: 

• Use Precise Triggers: Instead of the default “All Pages” trigger, set up specific triggers for each tag. For example, fire the conversion tracking tag only on the thank-you page after a purchase. 

• Segment by Page Type or User Action: Only load certain tags on product pages, blog posts, or after specific user interactions. 

• Avoid Loading Heavy Tags Sitewide: Tags for chat widgets, video tracking, or third-party integrations should be limited to pages where they’re actually needed. 

Benefits: 

• Reduces unnecessary HTTP requests. 

• Speeds up page load times by limiting the number of active tags. 

• Improves data accuracy by reducing noise from irrelevant pages.  

Example: If you have a Facebook Pixel for tracking purchases, set it to fire only on the order confirmation page, not across your entire site. 

3. Delay Non-Essential Tags

Some tags are important for marketing or analytics but don’t need to load immediately. By delaying their execution, you can prioritize the loading of critical content and improve perceived speed. 

How to Delay Tags: 

• Use “Window Loaded” or Custom Event Triggers: Set non-essential tags to fire after the main content loads or after a user action, such as scrolling or clicking. 

• Implement Time-Based Delays: Use JavaScript to trigger tags a few seconds after the page has loaded. 

• javascript: setTimeout(function() { dataLayer.push({‘event’: ‘delayedTag’}); }, 3000); // Fires after 3 seconds 

• Prioritize Tags: Identify which tags are mission-critical (e.g., analytics, conversion tracking) and which can be delayed (e.g., remarketing, chat widgets). 

Benefits: 

• Improves initial page load speed and user experience. 

• Ensures essential content is visible before secondary scripts run. 

• Reduces the risk of render-blocking issues. 

Considerations: Always test delayed tags to ensure they still capture the necessary data and do not interfere with user interactions. 

4. Optimize Trigger Conditions

Triggers that are efficient play a critical part in making sure tags fire only when there is a clear need, alongside avoiding superfluous work. 

How to Optimize Triggers: 

• Be Specific: Use triggers that match only the exact conditions required for the tag to fire. For instance, use “Page Path equals /checkout/thank-you” instead of “Page URL contains checkout.” 

• Combine Conditions:  Implement multiple requirements within a single trigger to specify even further the criteria under which a tag can fire. For example, fire a tag only if the user stands on a specific page AND interacts with a particular button. 

• Avoid Broad Triggers: Refrain from using “All Pages” unless it’s necessary for the tag’s function. 

Benefits: 

• Reduces the number of times tags are evaluated and fired. 

• Minimizes the impact on page performance. 

• Helps maintain data quality by avoiding accidental double-counting or misfires. 

Example: For an event tracking tag, set the trigger to fire only when a user clicks a specific CTA button rather than on any click across the site.

5. Minimize and Optimize Variables

Variables in GTM are used to capture dynamic values (like page URLs, click text, or custom JavaScript outputs) and pass them to tags. However, too many variables-especially custom JavaScript variables-can slow down your site. 

How to Optimize Variables: 

• Remove Unused Variables: Regularly review your variable list and delete those that are no longer in use. 

• Use Built-In Variables: Whenever possible, rely on GTM’s built-in variables, which are optimized for performance. 

• Limit Custom JavaScript: Custom JavaScript variables can be powerful but are also resource-intensive. Use them sparingly and ensure the code is efficient.

Benefits: 

• Reduces the processing load on each page. 

• Makes the GTM container easier to manage. 

• Improves overall site speed and reliability. 

Pro Tip: Document your variables and their purposes to avoid confusion and duplication as your GTM setup grows.

6. Use Asynchronous Loading

By default, GTM loads asynchronously, but it’s essential to ensure that all your tags and third-party scripts do as well. 

How Asynchronous Loading Works: 

• Async Scripts: When a script is loaded asynchronously, the browser can continue rendering the page while the script loads in the background. 

• GTM Snippet Placement: Place the GTM container snippet as recommended by Google immediately after the opening <head> tag for the main script and after the opening <body> tag for the noscript fallback. 

Benefits: 

• Prevents scripts from blocking the rendering of critical content. 

• Enhances perceived load speed for users. 

• Reduces the risk of “render-blocking resources” warnings in speed testing tools. 

Example Implementation: xml <script async src=”https://www.googletagmanager.com/gtm.js?id=GTM-XXXX”></script> 

 Considerations: While most tag templates in GTM are designed to load asynchronously, always check third-party scripts for compatibility and update them if needed.

7. Regular Container Audits

Ongoing maintenance is essential for keeping your GTM setup lean and efficient. 

How to Conduct Regular Audits: 

• Schedule Reviews: Set a recurring calendar reminder to audit your GTM container-quarterly is a good starting point. 

• Check for Orphaned Tags, Triggers, and Variables: Remove anything that’s no longer in use. 

• Test Tag Firing: Use GTM’s Preview and Debug mode to ensure tags are firing as intended and not causing performance issues. 

• Collaborate with Stakeholders: Involve marketers, developers, and analysts in the audit process to ensure all perspectives are considered.

Benefits: 

• Prevents tag bloat and performance degradation over time. 

• Ensures your tracking setup evolves with your business needs. 

• Helps catch and fix errors before they impact users or data quality. 

Pro Tip: Document changes and maintain a change log for future reference and troubleshooting.