GTM Once-Per-Session Trigger Architecture

Why This Exists

The current GTM implementation contains multiple click, scroll, and engagement events configured as GA4 key events/conversions.

Because these events can fire repeatedly within a single user session, they can artificially inflate conversion counts and negatively impact:

• Google Ads Smart Bidding
• Performance Max learning

To mitigate this issue while preserving reporting visibility, the events below should fire:

ONE TIME PER SESSION

How Session Storage Works

The implementation uses the browser's sessionStorage API.

Session storage persists data:

• For the duration of the browser tab/session
• Until the tab/browser is closed
• Across page navigations within the same session

Example

sessionStorage.setItem('linkedin_click', 'true');
  

Once set, GTM can check whether the event already occurred:

sessionStorage.getItem('linkedin_click');
  

Action	Behavior
First click in session	Event fires
Second click same session	Blocked
Refresh page	Still blocked
Close browser tab	Session resets
New session tomorrow	Can fire again

Reusable GTM Variable

Custom JavaScript Variable

Name: JS - Event Once Per Session

function() {

  var type = '';
  var identifier = '';

  // VIDEO EVENTS
  if ({{Video Percent}}) {

    type = 'video';

    var videoUrl = {{Video URL}} || '';

    var cleanVideo = videoUrl
      .replace(/^https?:\/\/(www\.)?/i, '')
      .replace(/[?#].*$/, '');

    identifier =
      cleanVideo +
      '_' +
      {{Video Percent}};

  // SCROLL EVENTS
  } else if ({{Scroll Depth Threshold}}) {

    type = 'scroll';

    identifier = {{Scroll Depth Threshold}};

  // CLICK EVENTS
  } else {

    type = 'click';

    identifier =
      {{Click URL}} ||
      {{Click Text}} ||
      {{Click ID}} ||
      {{Click Classes}};

  }

  // Prevent invalid values
  if (
    identifier === undefined ||
    identifier === null ||
    identifier === ''
  ) {
    return false;
  }

  var normalized = identifier
    .toString()
    .toLowerCase()
    .trim()
    .replace(/\s+/g, '_')
    .replace(/[^a-z0-9_\-\/]/g, '');

  var key = 'session_event_' + type + '_' + normalized;

  // Already fired this session
  if (sessionStorage.getItem(key)) {
    return false;
  }

  // Set session flag
  sessionStorage.setItem(key, 'true');

  return true;

}
  

This creates a unique session key dynamically based on:

• Event type (video, scroll, click)
• Video URL + percentage (for video events)
• Scroll threshold (for scroll events)
• Click URL, Text, ID, or Classes (for click events)

Simple Configuration - Just Add One Condition

Once you've added the JS - Event Once Per Session variable, you only need to update your existing triggers by adding ONE condition.

This is the most elegant solution with your current GTM setup:

Step-by-Step Configuration

1. Open each of your 12 triggers (LinkedIn, Facebook, Apple Store, Google Play, Telephone, Book a Demo, Get Access Now, Give it a Try, Learn More, Sign In, Scroll Depth, Video)
2. Add a new condition: JS - Event Once Per Session equals true
3. That's it - no complex changes needed

Visual Example

Below is an example of how simple the trigger configuration is:

✓ Total time to configure all 12 triggers: ~5 minutes

Recommended Trigger Architecture

Trigger	Current Logic	Recommended Logic
LinkedIn Click	Click URL contains linkedin.com	Click URL contains linkedin.com AND JS - Event Once Per Session = true
Facebook Click	Click URL contains facebook.com	Click URL contains facebook.com AND JS - Event Once Per Session = true
Apple Store Click	Click URL contains apps.apple.com	Click URL contains apps.apple.com AND JS - Event Once Per Session = true
Google Play Click	Click URL contains play.google.com	Click URL contains play.google.com AND JS - Event Once Per Session = true
Telephone Link Click	Click URL contains tel:	Click URL contains tel: AND JS - Event Once Per Session = true
Book a Demo	Click Text contains Book a demo	Click Text contains Book a demo AND JS - Event Once Per Session = true
Get Access Now	Click Text contains Get access now	Click Text contains Get access now AND JS - Event Once Per Session = true
Give it a Try	Click Text contains Give it a try	Click Text contains Give it a try AND JS - Event Once Per Session = true
Learn More	Click Text contains Learn more	Click Text contains Learn more AND JS - Event Once Per Session = true
Sign In	Click Text contains Sign In	Click Text contains Sign In AND JS - Event Once Per Session = true

Scroll Depth Events

Scroll depth events should also be deduplicated once per session PER percentage threshold.

Example

Threshold	Behavior
25%	Can fire once per session
50%	Can fire once per session
75%	Can fire once per session
90%	Can fire once per session

This prevents:

• Repeated firing on SPA navigation
• Scroll restoration duplication
• Inflated engagement conversions

Example Session Keys

session_event_scroll_25
session_event_scroll_50
session_event_scroll_75
session_event_scroll_90
  

YouTube / Media Events

Video progress events should also fire:

ONE TIME PER SESSION PER VIDEO PERCENTAGE

Video Event	Behavior
10%	Once per session
25%	Once per session
50%	Once per session
75%	Once per session
90%	Once per session
Complete	Once per session

Example Session Keys

session_event_video_10
session_event_video_25
session_event_video_50
session_event_video_75
session_event_video_90
session_event_video_complete
  

This prevents repeated playback loops, autoplay restarts, and duplicate engagement inflation.