Install SourceTag via Google Tag Manager

If you manage your site’s scripts through Google Tag Manager (GTM), you can add SourceTag as a Custom HTML tag. This keeps all your tracking scripts in one place.

Step 1: Copy your script tag

In your SourceTag dashboard, go to your site’s detail page and copy the script tag. It looks like:

<script src="https://cdn.sourcetag.io/scripts/YOUR_SITE_ID/st.js"></script>

Step 2: Create a new tag

1. Open your GTM container at tagmanager.google.com
2. Go to Tags in the left sidebar
3. Click New
4. Name the tag something clear, like “SourceTag Attribution Script”

Step 3: Configure the tag

1. Click Tag Configuration
2. Select Custom HTML
3. Paste the script tag in the HTML field:

<script src="https://cdn.sourcetag.io/scripts/YOUR_SITE_ID/st.js"></script>

Step 4: Set the trigger

1. Click Triggering
2. Select All Pages (the built-in Page View trigger)
3. Click Save

This fires the tag on every page load across your site.

Step 5: Publish the container

1. Click Submit in the top right corner
2. Add a version name like “Added SourceTag”
3. Click Publish

The tag is now live. GTM injects the SourceTag script on every page where your GTM container is installed.

Step 6: Test

You can test before publishing using GTM’s Preview mode:

1. Click Preview in GTM
2. Enter your site URL with UTM parameters:

https://yoursite.com/?utm_source=test&utm_medium=cpc&utm_campaign=gtm-test

3. In the GTM debug panel, confirm the “SourceTag Attribution Script” tag fired on the Page View event
4. Open your browser’s developer tools and check Application > Cookies for a _sourcetag cookie
5. Submit a form on your site and check the submission for attribution data

Important: tag firing order

SourceTag needs to run before any form submission happens. The All Pages trigger fires on the Page View event, which is early enough for most forms. However, if you have forms that load very early or via AJAX, be aware that:

• SourceTag uses a MutationObserver to detect forms added to the page after initial load, so dynamically loaded forms are handled
• If you’re using GTM’s built-in form submission tracking, SourceTag’s hidden fields will be populated before GTM captures the form data

Notes

• This works with any website that has GTM installed, regardless of platform.
• If you’re also using GTM to manage cookie consent, you can add a consent condition to the SourceTag tag’s trigger. For example, fire only after the visitor has accepted marketing cookies.
• Browser cookies are limited to 7 days when the script is loaded via GTM (since it’s still a JavaScript cookie). For longer persistence, use the WordPress plugin or the Cloudflare Worker for server-side cookies.
• If you have multiple environments in GTM (staging, production), make sure to publish to the correct environment.