Google Tag Manager Implementation Reference

Detailed guide for implementing tracking via Google Tag Manager.

Contents

• Container Structure (tags, triggers, variables)
• Naming Conventions
• Data Layer Patterns
• Common Tag Configurations (GA4 configuration tag, GA4 event tag, Facebook pixel)
• Preview and Debug
• Workspaces and Versioning
• Consent Management
• Advanced Patterns (tag sequencing, exception handling, custom JavaScript variables)

Container Structure

Tags

Tags are code snippets that execute when triggered.

Common tag types:

• GA4 Configuration (base setup)
• GA4 Event (custom events)
• Google Ads Conversion
• Facebook Pixel
• LinkedIn Insight Tag
• Custom HTML (for other pixels)

Triggers

Triggers define when tags fire.

Built-in triggers:

• Page View: All Pages, DOM Ready, Window Loaded
• Click: All Elements, Just Links
• Form Submission
• Scroll Depth
• Timer
• Element Visibility

Custom triggers:

• Custom Event (from dataLayer)
• Trigger Groups (multiple conditions)

Variables

Variables capture dynamic values.

Built-in (enable as needed):

• Click Text, Click URL, Click ID, Click Classes
• Page Path, Page URL, Page Hostname
• Referrer
• Form Element, Form ID

User-defined:

• Data Layer variables
• JavaScript variables
• Lookup tables
• RegEx tables
• Constants

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Naming Conventions

Recommended Format

B0

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Data Layer Patterns

Basic Structure

B1

Page Load Data

B2

Form Submission

B3

Button Click

B4

E-commerce Events

B5

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Common Tag Configurations

GA4 Configuration Tag

Tag Type: Google Analytics: GA4 Configuration

Settings:

• Measurement ID: G-XXXXXXXX
• Send page view: Checked (for pageviews)
• User Properties: Add any user-level dimensions

Trigger: All Pages

GA4 Event Tag

Tag Type: Google Analytics: GA4 Event

Settings:

• Configuration Tag: Select your config tag
• Event Name: {{DL - event_name}} or hardcode
• Event Parameters: Add parameters from dataLayer

Trigger: Custom Event with event name match

Facebook Pixel - Base

Tag Type: Custom HTML

B6

Trigger: All Pages

Facebook Pixel - Event

Tag Type: Custom HTML

B7

Trigger: Custom Event - form_submitted

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Preview and Debug

Preview Mode

1. Click "Preview" in GTM
2. Enter site URL
3. GTM debug panel opens at bottom

What to check:

• Tags fired on this event
• Tags not fired (and why)
• Variables and their values
• Data layer contents

Debug Tips

Tag not firing:

• Check trigger conditions
• Verify data layer push
• Check tag sequencing

Wrong variable value:

• Check data layer structure
• Verify variable path (nested objects)
• Check timing (data may not exist yet)

Multiple firings:

• Check trigger uniqueness
• Look for duplicate tags
• Check tag firing options

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Workspaces and Versioning

Workspaces

Use workspaces for team collaboration:

• Default workspace for production
• Separate workspaces for large changes
• Merge when ready

Version Management

Best practices:

• Name every version descriptively
• Add notes explaining changes
• Review changes before publish
• Keep production version noted

Version notes example:

B8

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Consent Management

Consent Mode Integration

B9

GTM Consent Overview

1. Enable Consent Overview in Admin
2. Configure consent for each tag
3. Tags respect consent state automatically

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Advanced Patterns

Tag Sequencing

Setup tags to fire in order: Tag Configuration > Advanced Settings > Tag Sequencing

Use cases:

• Config tag before event tags
• Pixel initialization before tracking
• Cleanup after conversion

Exception Handling

Trigger exceptions - Prevent tag from firing:

• Exclude certain pages
• Exclude internal traffic
• Exclude during testing

Custom JavaScript Variables

B10

For monetary tracking, prefer the numeric amount and currency from the application data layer. If a DOM variable is needed, have the application render data-price as an unformatted, non-negative decimal in major currency units; pass its currency separately. Do not infer the amount or currency from presentation text: parseFloat turns $1,234.56 into 1 after removing $, and localized separators have different meanings. A missing or invalid amount returns null, so skip that monetary event or diagnose it before sending; reserve 0 for an explicitly free item.