PerfectPixel by WellDoneCode is a Chrome, Edge, and Opera extension that drops a semi-transparent image overlay on top of any live webpage so you can line it up against the rendered page.
It lets you lay your actual design mockup over the shipped site and toggle opacity or blend modes to see, pixel by pixel, where the built page drifts from the file: catching spacing, sizing, and alignment gaps that are tedious to eyeball through devtools alone.
Pull it out during a design QA pass right after a page ships: drop in the Figma or PSD export, nudge it into place, and flip opacity back and forth to catch anything the build got slightly wrong.
The free version carries ads and caps you to basic overlay controls; layer rotation, ad removal, and extra customization are locked behind the paid Pro upgrade.
Overlay a semi-transparent image over HTML for pixel-perfect comparison.
