How PDF Difference Checkers Work: Text Extraction vs Visual Pixel Diffing

Published: 2026-02-21 | Read Time: 6 min read

A deep dive into how online PDF comparison tools detect modified text, changed layout elements, and revised legal clauses between two versions of a document.

Frequently Asked Questions

Can PDF comparison detect changes in scanned paper documents?

Yes! Scanned PDF documents undergo browser-based OCR preprocessing to extract text before executing string diffing algorithms.