Verify GTM is firing on your site

This guide shows you three ways to confirm GTM Kit is loading your container and pushing events to the data layer.

Why this matters

A misconfigured CMP, cache plugin, or theme can silently break tracking even when your settings look correct. Always verify after install and after any change to consent, caching, or container settings.

Method 1: Inspect the page source (fastest)

  1. Open your public site in a normal browser tab (not an admin tab).
  2. Right-click the page and choose View Page Source, or press Cmd or Ctrl + U.
  3. Search for your container ID, for example GTM-K8VHX.

You should find it in two places near the top of the document: a <script> tag inside the <head> and a <noscript> tag right after the opening <body>. If both are present, the container is being injected.

If you find neither, see The container snippet is not loading.

Method 2: Check the dataLayer in DevTools

  1. Open your site in a regular browser tab.
  2. Open DevTools (F12 or Cmd or Ctrl + Option + I).
  3. Switch to the Console tab.
  4. Type:
window.dataLayer

You should see an array of objects. The first few entries are typically:

[
  { 'gtm.start': 1714382400000, event: 'gtm.js' },
  { event: 'gtm.dom', ... },
  { event: 'gtm.load', ... },
  { event: 'page_view', page_type: 'post', ... }
]

The page_view event with GTM Kit’s post and page metadata confirms GTM Kit is pushing data, not just that the container is loading.

To watch new pushes live:

window.dataLayer.push = (function (orig) {
  return function (data) {
    console.log('dataLayer push:', data);
    return orig.apply(this, arguments);
  };
})(window.dataLayer.push);

Then click around your site. Each event will be logged to the console.

Method 3: Use Google Tag Manager Preview mode

This is the authoritative test. It connects your real browser to your real GTM workspace and shows you exactly which tags fire, which triggers match, and what variables resolve to.

  1. In Google Tag Manager, open your container.
  2. Click Preview in the top right.
  3. In the popup, enter your site URL and click Connect.
  4. A new tab opens on your site with a debug banner at the bottom and the Tag Assistant in the original tab.
  5. Click around your site. The Tag Assistant lists every event in chronological order, with the data layer state at each event.

Confirm the events you expect: page_view on every page, view_item on a product page, add_to_cart when you click an Add to cart button, and so on.

Common issues

Source view shows the container but the dataLayer is empty. GTM Kit is loading the container but not pushing events. Check that the integration toggle for the plugin in question is on under GTM Kit, Integrations. Also check that you are not excluded from tracking by user role (see Exclude logged-in users from tracking).

Tag Assistant says “no GTM container found” or fails to connect. The most common cause is that GTM Kit’s container injection is disabled (see Disable container injection) and nothing else is loading the container. Check GTM Kit, General and confirm Inject Container Code is on, or that whatever else was supposed to load the container is actually doing so.

Events fire in the dataLayer but tags do not fire in Tag Assistant. That is a GTM tag configuration problem, not a GTM Kit problem. Check the trigger conditions on the tag in your GTM workspace.

page_view fires in the dataLayer but not for logged-in users. You are excluded by user role. Open wp-admin/admin.php?page=gtmkit_general and review the Exclude user roles field.