GA4 integrity

Executive Summary

Vampire Vape's GA4 property (354471494) is broadly healthy with a trust score of 86, recording 22,444 purchases and £710,750 in revenue during the audit window — but two issues threaten the reliability of that data. Seventeen product and category URLs are returning zero page_view events, creating blind spots across key SKUs and brand pages that will distort attribution and merchandising decisions. A 61% spike in session_start events also signals a likely tagging regression that could be inflating session counts and skewing all downstream channel and conversion metrics.

Key metrics

Ecommerce funnel

Top recommendations

1. CRITICAL Fix missing begin_checkout events in the purchase funnel

   begin_checkout is recording 0 events against 73,057 add_to_cart and 22,444 purchase events, meaning the checkout funnel is completely blind — checkout abandonment, step-level drop-off, and funnel reports in GA4 are all unusable, directly undermining conversion optimisation decisions.

   How to fix

   1. Open GTM Preview mode and add a product to cart on www.vampirevape.co.uk, then proceed to the checkout page — confirm whether a dataLayer.push containing event: 'begin_checkout' fires by inspecting the Data Layer panel in GTM Preview.
   2. If no dataLayer event fires, locate the checkout page template in your ecommerce platform (e.g. WooCommerce, Magento, Shopify) and add a dataLayer push for begin_checkout with the items array (item_id, item_name, price, quantity) and currency and value parameters, following the GA4 ecommerce spec.
   3. In GTM, create or update a GA4 Event tag of type 'GA4 Event', set the Event Name to begin_checkout, and add ecommerce parameters: currency, value, and items (mapped from the dataLayer variable ecommerce.items).
   4. Set the trigger to fire on the checkout URL path (e.g. Page Path contains /checkout) or on the custom dataLayer event begin_checkout — whichever matches your implementation.
   5. Publish the GTM container, then validate in GA4 DebugView (Admin > DebugView) by walking through a real checkout session and confirming the begin_checkout event appears with the correct items, value, and currency parameters.
   6. After 48 hours of live data, open GA4 > Reports > Monetisation > Purchase Journey and confirm the begin_checkout step is now populated between add_to_cart and purchase.

2. HIGH Investigate and resolve 17 URLs with zero page_view events

   critical revenue-driving pages — including the flagship /brands/vampire-vape brand hub, the high-margin /heisenberg-nic-salts category, and multiple product detail pages — are invisible in GA4, meaning traffic, product performance, and category-level merchandising reports are incomplete and untrustworthy.

   How to fix

   1. Take the 17 URLs from the evidence list and open each in GTM Preview mode (gtm.google.com > Preview, enter the URL) — check whether the GA4 Configuration tag (or GA4 Event tag firing page_view) appears in the Tags Fired panel on page load.
   2. For any URL where the GA4 tag does NOT fire, inspect the tag's trigger — if it uses a Page Path or Page URL trigger, confirm the path exactly matches (e.g. /heisenberg-nic-salts vs /heisenberg-nic-salts/) and correct any trailing-slash or case mismatches in GTM > Triggers.
   3. For product pages such as /uwell-crown-x-vape-pod-kit-red and /smok-ipx-80-replacement-pods-3pk, confirm the page template renders the GTM snippet — if these are dynamically generated pages, check that the GTM container snippet (GTM-XXXXXX) is present in the page source via View Page Source.
   4. If pages are live and the tag fires but GA4 still shows zero sessions, check GA4 Admin > Data Filters to confirm no internal traffic or developer filter is excluding these URLs, and verify the Measurement ID on the firing tag matches property 354471494.
   5. For any pages confirmed to have genuinely zero organic traffic (e.g. discontinued SKUs like /innokin-scion-ii-coil-0-36ohm-4-core-3-pk), flag them to the merchandising team for review and remove from the audit tracking config.
   6. Validate the fix in GA4 Realtime report (Reports > Realtime) by navigating to each corrected URL in a browser and confirming a page_view event appears with the correct page_location parameter.

3. HIGH Diagnose the 61% session_start spike to confirm data integrity

   a jump from 120,742 to 193,963 session_start events (+61%) is abnormal and suggests either a GTM container change that is double-firing the GA4 Configuration tag or a theme/platform deploy that injected a duplicate tracking snippet — both scenarios inflate session counts, corrupt channel attribution, and make all period-over-period performance comparisons unreliable.

   How to fix

   1. In GTM > Versions, review the version history and identify any container publishes that coincide with the start of the spike — note the publish date and the tags/triggers that were changed.
   2. Check your ecommerce platform's deploy log (e.g. WooCommerce update history, Shopify theme versions, or your CI/CD pipeline) for any theme or plugin updates that went live around the same date.
   3. Open GTM Preview on www.vampirevape.co.uk and load the homepage — in the Tags Fired panel on the initial Page Load event, count how many GA4 Configuration tags fire; there must be exactly one instance of the tag linked to Measurement ID G-XXXXXXX (matching property 354471494).
   4. If two or more GA4 Configuration tags fire, identify the duplicate — either a hardcoded gtag.js snippet added directly to the theme, or a second GTM tag — and remove it: for a hardcoded snippet, delete it from the theme header template; for a duplicate GTM tag, pause it in GTM > Tags and republish.
   5. In GA4 Admin > DebugView, load several pages and confirm only one session_start event fires per new session, with no repeated session_start events on the same page.
   6. Monitor GA4 Realtime and the session_start event count in GA4 > Explore > Free Form over the following 7 days to confirm the metric returns to a baseline consistent with the prior period (~120,000 range).

4. MEDIUM Tag the 17 zero-view pages with view_item events for product detail pages

   product detail pages such as /uwell-crown-x-vape-pod-kit-red and /smok-nord-5-replacement-pods-3pk must fire view_item events to appear in GA4's Ecommerce reports and feed accurate product-level impression data into item-scoped dimensions — without this, product performance reports undercount impressions and distort add-to-cart rates for those SKUs.

   How to fix

   1. Once the page_view coverage issue (above) is resolved and GTM fires on these templates, open GTM and locate the existing GA4 Event tag for view_item — confirm it is present and that its trigger fires on all product detail page paths, not just a subset.
   2. If the trigger is a Page Path trigger, update it to use a regex that covers all product URL patterns (e.g. Page Path matches RegEx ^/[a-z0-9-]+-(?:kit|pod|coil|tank|shot|pouch|glass|concentrate) or broaden to fire on all pages that include a productDetail dataLayer push).
   3. Verify that the view_item dataLayer push on each product page includes the required ecommerce parameters: items array with item_id (SKU), item_name, item_category, price, and currency — cross-reference against your product template's dataLayer output in GTM Preview > Data Layer.
   4. In GTM, map the items parameter in the GA4 Event tag using a Data Layer Variable scoped to ecommerce.items, and ensure currency is mapped from ecommerce.currency.
   5. Publish the updated GTM container and validate in GA4 DebugView by loading /smok-ipx-80-replacement-pods-3pk — confirm the view_item event fires with item_id, item_name, price, and currency visible in the event parameters panel.

Findings

Trend vs previous period