The Ultimate GTM Audit Checklist: 20 Things to Check Before Your Tracking Breaks

Google Tag Manager is the backbone of modern marketing measurement. But over time, containers accumulate technical debt: deprecated tags, duplicate triggers, and misconfigured variables. This comprehensive GTM audit checklist will help you identify issues before they cost you money.

Table of Contents

• Why Audit Your GTM Container?
• Container Hygiene
• Tag Configuration
• Trigger Accuracy
• Variable Best Practices
• Conversion Tracking
• Cross-Domain & E-commerce
• Audit Tools & Resources
• FAQs

Why Audit Your GTM Container?

Industry Insight: The average GTM container has 47 tags after 2 years of use. In our audits, we find that 20-30% of these tags are either broken, duplicated, or no longer needed.

A messy GTM container leads to:

Related: For GA4-specific issues, see our GA4 Tracking Audit Checklist.

Container Hygiene

✅ 1. Container Naming Convention

• Container name clearly identifies the website/property
• Version descriptions are meaningful (not "fixed stuff")
• A consistent naming scheme is followed

Good naming example:

Container: clientname.com - Production
Version 45: "Added LinkedIn Insight tag, fixed form submit trigger on /contact"

✅ 2. Folder Organization

• Tags are organized into logical folders
• Folder names describe function (e.g., "GA4", "Advertising", "Forms")
• No orphan tags sitting in root

Recommended folder structure:

📁 GTM Container
├── 📂 Analytics (GA4, GTM config)
├── 📂 Advertising (Google Ads, Meta, LinkedIn)
├── 📂 Forms (Contact, Demo, Newsletter)
├── 📂 E-commerce (Purchase, Add to Cart)
├── 📂 Utilities (Scroll depth, Timer, Custom)
└── 📂 Deprecated (Old tags awaiting removal)

✅ 3. Workspace Hygiene

• No stale workspaces older than 30 days
• Clear workspace ownership (who's working on what)
• Preview mode changes are published promptly

✅ 4. Container Export Backup

• Recent container export exists (JSON backup)
• Backups are version-controlled (Git or similar)
• Team knows how to restore from backup

Pro tip: Create a quarterly calendar reminder to export your container: GTM → Admin → Export Container.

Tag Configuration

✅ 5. GA4 Configuration Tag

• Exactly ONE GA4 Configuration tag
• Fires on "All Pages" trigger
• Send page_view is enabled (or deliberately disabled with custom page_view)
• Measurement ID is correct (not a dev property)

Common mistake: Multiple GA4 config tags causing duplicate page views. Check in GA4 DebugView or Real-time.

✅ 6. No Deprecated Tags

• Remove old Universal Analytics tags (UA-XXXXXXX)
• Remove deprecated Facebook Pixel (use Conversions API)
• Remove old Google Ads remarketing (migrate to Google Ads Remarketing via GA4)

How to find deprecated tags:

1. Sort tags by "Last edited"
2. Tags not edited in 12+ months are candidates for review
3. Pause before deleting—check if replacement exists

✅ 7. Tag Firing Sequence

• GA4 Config tag fires first (use tag sequencing if needed)
• Consent tags fire before marketing tags
• No race conditions between dependent tags

Use tag sequencing when:

• A tag depends on data from another tag
• Consent must be checked before marketing pixels fire
• Custom variables need to be set before events fire

✅ 8. Conversion Tags Configuration

• Each conversion action has ONE tag (not multiple)
• Conversion ID and labels are correct
• Enhanced conversions are configured (if applicable)
• Value and currency pass correctly

Learn more: How to Connect Google Ads to HubSpot for Revenue Attribution covers proper conversion setup.

Trigger Accuracy

✅ 9. Form Submit Triggers

• Form submit triggers use proper form identification (ID, class, or URL)
• Validation ensures only successful submissions fire
• No duplicate fires on same submission

Better than native form submit:

// Use thank-you page or success message detection
// Trigger: Page View
// Condition: Page URL contains "thank-you" OR 
//            Element exists: .form-success-message

✅ 10. Click Triggers

• Click triggers are specific (not firing on every click)
• Use Click Classes or Click ID, not just Click URL for CTAs
• Outbound link clicks are captured correctly

Trigger specificity check:

1. Preview your container
2. Click around the site
3. Watch the trigger panel—too many fires = too broad

✅ 11. Custom Event Triggers

• Custom events match exactly what's pushed to dataLayer
• Event name casing is correct (dataLayer is case-sensitive)
• Regex patterns are tested and documented

Example dataLayer push and matching trigger:

// dataLayer push (in your code)
dataLayer.push({
  'event': 'form_submission',
  'formName': 'contact_form'
});

// GTM Trigger: Custom Event
// Event name: form_submission

✅ 12. Scroll Depth Triggers

• Scroll depth percentages match business needs (25%, 50%, 75%, 90%)
• Vertical vs horizontal is set correctly
• Fires once per page (not continuously)

Variable Best Practices

✅ 13. Data Layer Variables

• Variable names match dataLayer keys exactly
• Default values are set for optional fields
• Nested values use dot notation correctly

Correct nested variable reference:

Variable Name: ecommerce.purchase.actionField.id
Data Layer Version: Version 2

✅ 14. User-Defined Variables

• No hardcoded values that should be variables (like measurement IDs)
• Constant variables used for reusable values
• Lookup tables are used for mapping values

Use a constant variable for IDs:

Variable: GA4 Measurement ID
Type: Constant
Value: G-XXXXXXXXXX

Then reference {{GA4 Measurement ID}} in all GA4 tags.

✅ 15. URL Variables

• Correct URL component is selected (path, query, fragment)
• Query parameters are captured for UTM tracking
• URL decoding is enabled where needed

Conversion Tracking

✅ 16. Conversion Deduplication

• Each conversion fires exactly ONCE per action
• Order ID or transaction ID is used for purchase conversions
• Timestamp or unique identifier prevents duplicate sends

Deduplication example for forms:

// Set a cookie or sessionStorage flag after submission
if (!sessionStorage.getItem('form_submitted')) {
  dataLayer.push({'event': 'form_submission'});
  sessionStorage.setItem('form_submitted', 'true');
}

Related: See how to fix duplicate conversions in Google Ads.

✅ 17. Enhanced Conversions

• User data variables are configured (email, phone, address)
• Data is hashed before sending (SHA-256)
• Enhanced conversions is enabled in Google Ads

✅ 18. Offline Conversion Tracking Setup

• GCLID is captured from URL parameters
• GCLID is stored in a cookie (90-day minimum)
• CRM receives GCLID with form submissions

Full implementation guide: Connect Google Ads to HubSpot for Revenue Attribution.

Cross-Domain & E-commerce

✅ 19. Cross-Domain Tracking

• Linker domains are configured if users cross domains
• _gl parameter passes correctly between domains
• Referral exclusions are set for owned domains

Check cross-domain setup:

1. Navigate from domain1.com to domain2.com
2. Check URL for _gl= parameter
3. Verify in GA4 that session continues (not a new user)

✅ 20. E-commerce Data Layer

• Product data structure matches GA4 requirements
• Currency is consistent across all events
• Item arrays include required fields (item_id, item_name)

Required e-commerce events:

• view_item
• add_to_cart
• begin_checkout
• purchase

Audit Tools & Resources

Audit Frequency Recommendations

Frequently Asked Questions

Answers to common GTM audit questions.

Need a Professional Audit?

If your GTM container has grown unwieldy or you suspect tracking issues, book a 15-minute call to discuss a Tracking & Attribution Fix project.

What's included:

• Complete GTM container audit with documentation
• Tag cleanup and optimization
• Trigger and variable best practices
• Conversion tracking verification
• SOP for ongoing maintenance