Tracking and measurement checks for your own site

Why tracking comes first

Ad platforms decide who sees your ads partly from the conversions your site reports back. If a tag is missing, fires twice or fires on the wrong page, the platform learns from bad data, your reports mislead you, and every change you make afterwards is judged on the wrong numbers.

In a channel comparison, tracking is often where the quickest fix sits. It is also the one channel you can check end to end, because you hold the logins.

The tags to check

For a UK online shop running paid ads, check:

• GA4, Google's analytics, on every page, with purchase or enquiry events on the confirmation step
• Google Ads tags, including conversion tracking on the confirmation step if you run Google Ads
• The Meta Pixel, with page views on every page and key events such as add to basket, checkout started and purchase
• The TikTok pixel, if you advertise on TikTok
• Consent mode, so that Google tags respect each visitor's consent choices

Service firms usually swap purchase events for form submissions, calls or bookings. The principle is the same: the event that matters to the business must be recorded once, on the right page, with the visitor's consent respected.

Checking your own site with Tag Assistant

Tag Assistant works with Tag Manager's preview mode to show which tags fired and in which order. A simple routine:

1. Open Tag Manager, start preview mode and enter your homepage address. Tag Assistant opens alongside your site.
2. Walk the key journey as a customer would: homepage, a category page, a product page, add to basket, checkout.
3. At each step, look at the list of tags that fired. Note anything that should have fired and did not, and anything that fired twice.
4. Complete a real low-value test order or enquiry if you can, then check the confirmation step fires the purchase or lead events once.
5. Repeat on a phone-sized browser window and, if you can, on a phone, because some themes load different scripts on mobile.

For the Meta Pixel and the TikTok pixel, each platform has its own browser helper and event testing view in the ad account. Use them alongside Tag Assistant rather than instead of it, and check the events reported there match what you did on the site.

Checking consent mode

Consent mode passes your visitors' consent choices to Google tags. It uses four consent types: ad_storage, analytics_storage, ad_user_data and ad_personalization.

Test both paths:

• Accept all. Load a fresh private window, accept cookies, and check in Tag Assistant that the consent state updates to granted and your tags behave as expected.
• Reject all. Load another fresh private window, reject, and check that the consent state shows denied and that tags respect it.

Common problems include a banner that loads after the tags, so the first page fires before any choice is made, and a banner that records a choice that is never passed on to the tags. If you use a consent platform, check its own documentation alongside Google's.

Reading page source

Page source is the raw HTML your browser receives. To read it, right-click the page and choose view page source, then use the browser's find function. Search for names such as gtag, googletagmanager, fbq, the Meta Pixel ID format, or ttq for TikTok.

On your own site this is a quick sanity check that the snippets are present on the pages they should be. It will not tell you whether events fire correctly, which is why Tag Assistant and the platforms' event testing views matter more.

Some tags load through Tag Manager and never appear directly in the source. If your source shows only the Tag Manager container, the detail lives inside the container, and preview mode is the place to inspect it.

What a rival's page source can and cannot tell you

Looking at a rival's public page source, or using a browser tag inspector on their public pages, is fair: it is what any visitor's browser receives. It can show:

• which analytics and ad tags appear to load on public pages
• whether a Tag Manager container is present
• whether a consent banner loads before or after the tags, as far as you can see as a visitor

It cannot show:

• whether their conversions are recorded accurately
• what fires on the confirmation step, unless you complete a real purchase, which you should not do purely for research
• how their ad accounts are set up or what they spend

Read rival tracking as a hint about how seriously they measure, not as a verdict. If Rival A loads the Meta Pixel, GA4 and Google Ads tags with consent mode, and you load only GA4, that is a gap worth closing on your own site regardless of how well theirs works.

Keep checking after changes

Tracking breaks quietly. A theme update, a new checkout app or a change of consent banner can remove or duplicate a tag without anyone noticing. Re-run the Tag Assistant routine after any change to the site's theme, checkout or cookie banner, and before any large campaign.

Our own ads audit loop, which will read the accounts these tags feed, is in build and not on sale. Until it ships, run the routine above after every theme, checkout or banner change.