What this tool checks
It opens your page in a real Chrome browser with no cookies, no login and no ad blocker — a genuinely first-time visitor — and records every network request the page makes. If a cookie banner appears, it clicks accept and records again, so you can see the difference consent makes.
Why is my Meta pixel not firing?
Usually one of four things: the pixel script never loads, it loads but no event is sent, a cookie banner is blocking it until consent, or it is firing correctly and your own browser is showing you something different because of an ad blocker or prior consent state.
That last one catches people out constantly. Your browser carries months of history — accepted banners, logged-in sessions, extensions. It is not a reliable way to judge what a new visitor experiences. Checking as a clean first-time visitor is the only way to see what most of your traffic actually sends.
One genuine limitation worth knowing: Meta sometimes sends events by POST, where event names travel in the request body rather than the URL. A browser watching from outside cannot always read those. If a pixel shows as firing but with no event names, that is often why — and it means the pixel is working, not broken.
How do I know if GA4 is tracking correctly?
A healthy GA4 setup sends page_view on every page, plus events that match what the page is for. A product page with no view_item, or a checkout with no begin_checkout, means the data exists but the behaviour does not.
The most common failure is not a missing tag. It is a site that tracks only page views. GA4 records that people arrived and nothing about what they did, which means no campaign can ever be judged on outcomes — only on traffic. Ad platforms then optimise toward clicks because clicks are the only signal you gave them.
Note that ecommerce events legitimately do not fire on a homepage. Missing add_to_cart there is correct behaviour, not a bug. Check a product page before concluding anything.
What happens if two GTM containers load on the same page?
Every event gets counted twice, which inflates conversions, sessions and revenue in every platform reading that data — and makes your cost-per-result look roughly half of what it really is.
It happens more often than people expect, usually when a container is hardcoded into a theme and then added again through a plugin or a developer. The symptom is numbers that look suspiciously good against a bank balance that does not agree.
Do pixels have to wait for cookie consent?
For visitors in the EU and UK, yes. Analytics and advertising tags are non-essential, so under GDPR they must not fire until the visitor actively accepts. A banner that describes cookies while the pixel already fired is not compliant.
This is the single most common finding on sites that believe they are compliant, because installing a banner and gating the tags behind it are two separate pieces of work, and only the first is visible. If tags fire before you click accept, the banner is decoration.