Click to upload first PDF
or drag & dropClick to upload second PDF
or drag & dropView two PDF files side by side, page by page, and visually highlight where their content differs — processed entirely in your browser.
This tool runs entirely client-side: neither PDF is uploaded to a server. Both files are opened and rendered with PDF.js, displaying matching page numbers from each document next to each other so you can visually scan for differences as you navigate through the pages.
When you run "Highlight Differences," both currently displayed pages are rendered to identical-sized canvases, and the tool performs a pixel-by-pixel comparison — reading the RGB color values at every pixel position in both images and flagging any pair where the combined color difference exceeds a threshold.
Differing pixels are highlighted directly on an overlay canvas, and a percentage is calculated showing roughly what portion of the page differs, giving you a quick visual and quantitative signal of how much changed between the two versions of that page.
