Meta (Facebook) Pixel Explained: What It Is & How to Check It

The Meta Pixel (formerly the Facebook Pixel) tracks visitor actions on your site for Facebook and Instagram ad targeting, retargeting and conversion measurement.

What the pixel ID means

Each pixel has a numeric ID (15–16 digits) tying data to your Meta Business account. You’ll see it loaded via connect.facebook.net and the fbq() function.

Standard and custom events

Beyond the base PageView, the pixel sends events like ViewContent, AddToCart and Purchase, which power conversion optimisation and Custom Audiences.

Watch for duplicates

A very common mistake is the same pixel ID firing twice — once hard-coded and once via GTM. That double-counts events. Tag Explorer flags duplicate IDs automatically.

How to check yours is working

Run your site through our free Tag Explorer tool — it shows every tag on the page, nested under its GTM container, with the tracking IDs. To confirm a tag actually fires, use GTM’s Preview mode or your browser’s DevTools Network tab.

---

Part of the Shipwreck Studio Tag Guide. Scan any page with Tag Explorer to see its full tag tree and spot duplicates.