Compare two PDF files and see exactly what changed. Upload an original and a revised PDF and PDF4 highlights the differences — text or visual — instantly, securely, and right in your browser.
Yes. You can compare two PDF files online for free — no account, email, or credit card required. Sign up only if you want higher limits, larger files, or API access.
Text comparison runs a line-by-line diff of the extracted text on each page, showing exactly what was added or removed. Visual comparison renders the original and revised pages side by side in a single PDF so you can spot layout, image, and formatting changes at a glance.
Yes. Uploads travel over an encrypted HTTPS connection, are processed on our servers, and are automatically deleted within a few hours. We never share or sell your documents.
No. PDF4 works entirely in your web browser, so there is nothing to download or install. It runs on Windows, macOS, Linux, Android, and iOS.