What is the Custom Loader?
The Custom Loader is an add-on that replaces the standard loading of Google Tag Manager from https://www.googletagmanager.com/gtm.js with a custom loader script served directly from your domain (e.g. https://track.yourdomain.cz/l/gtm.js).
Why use the Custom Loader?
- Bypasses ad-blockers: Ad-blockers block gtm.js from the Google domain, but not from your own.
- Raises the cookie match rate: First-party cookies have a longer lifetime (up to 2 years vs. 7 days in Safari).
- Better data: 30-40% more visitors with full tracking.
How to activate
- Go to Dashboard → Add-ons
- Turn on the "Custom Loader" toggle
- Select the domain (it must have an active sGTM container)
- Enter the GTM Container ID (e.g. GTM-XXXXXX)
- Choose the platform:
gtm,gtag, orga4 - Optionally: enable GA4 bypass, a Custom DataLayer variable, Cookie Keeper
- Click "Save Custom Loader"
- The loader will be available at:
https://your-domain.cz/l/gtm.js
Integration into the site
Replace the standard GTM snippet in your <head>:
<!-- Instead of the standard GTM -->
<script async src="https://track.yourdomain.cz/l/gtm.js"></script>Advanced options
- GA4 Bypass: Adds direct GA4 measurement alongside GTM (dual tracking).
- Custom DataLayer: Uses a custom dataLayer variable name (e.g.
myDataLayer). - Cookie Keeper: Automatically backs up cookies to localStorage.
- User Identifier: Adds a custom user identifier to all events.
💡 Tip:
Use the Custom Loader in combination with the Cookie Keeper add-on for maximum protection against ITP/ETP.