Free GA4 tag and Consent Mode checker
Built by Marc Alexander. Paste in a page from your site and see exactly what a first-time visitor triggers before they've agreed to anything: tags, pixels and consent signals, ranked by how much they matter.
What it checks
- Google Tag Manager or GA4 installed more than once
- Page views counted twice
- More than one GA4 measurement ID on the page
- Consent Mode missing, or version 1 only
- Consent defaults set too late to count
- A cookie banner that doesn't actually block anything
- Meta automatic advanced matching and automatic events
- Missing deduplication IDs on Meta, TikTok and Reddit
- Server-side tagging, and a security policy that may be blocking tags
- How much each tracking tool slows the page on a phone
- Tracking scripts that hold up the page from appearing
What it can't see
Some problems only show up on a real journey with a real basket. The checker can't see:
- Whether purchases are counted once, in practice
- Whether transaction IDs survive a refresh
- Whether cross-domain tracking carries the session on click
- Settings inside your GA4 account, such as referral exclusions
- Cookies and the dataLayer (the scan sees requests only)
- How your site behaves for UK visitors specifically: the scan runs on Google's servers, which may be outside the UK
That's what the GA4 audit is for. The checker shows there's a problem; the audit confirms it and fixes it.
Questions
Is the tracking checker free?
Yes. It loads one page of your site and shows what fires, with no sign-up. If you want Marc to look at the results, you can send them to him from the report.
What does the checker do to my site?
Nothing. Google PageSpeed Insights opens a single page in a clean browser on a simulated phone, as a first-time visitor who hasn't accepted or declined cookies, and the checker reads every request it made and how long each script kept the browser busy. It doesn't click anything, fill in forms or change any settings.
Why test before consent?
Under UK GDPR and PECR, non-essential cookies and tracking need consent first. The moment before a visitor makes a choice is where most setups go wrong, and it is the hardest moment to test by hand, because your own browser already remembers your choice.
Can a single page load find every tracking problem?
No. It finds problems that show up on a cold page load, such as duplicate tags, consent timing. Problems that need a real journey, such as purchase deduplication and checkout attribution, need an audit with a real basket.
Does the checker keep my data?
No. The checker loads the page, returns the findings to your browser and keeps nothing. If you choose to send your results to Marc, he receives the page address, the findings and your email address, and uses them only to reply to you.
Talk to Marc about it
Tell Marc what's happening with your tracking. The quickest place to start is usually a GA4 mini audit: a prioritised list of what's broken and what to fix first.
Mini audit from £175.
Prefer to talk first? Choose "20-minute intro call" in the form.
Or email [email protected].