Facebook Pixel Checker
Verify the Meta Pixel is present on a page and see its pixel ID. Also flags Google Tag Manager, since pixels are often installed through it.
The pixel is not enough anymore
Ad blockers stop the pixel for a fifth of visitors or more, and iOS truncates its attribution. Meta itself recommends pairing it with the Conversions API. PixelFox sends CAPI events with the same event_id, so nothing double-counts.
Add Conversions API