Harsh Mohan

About

Harsh Mohan is the founder and developer of PDF Zone. He built every tool on the site, from the merge and split operations through to redaction, OCR and PDF/A conversion, and wrote the guides that explain them.

PDF Zone exists because of a specific technical position: PDF processing does not need a server. Every operation here runs in the browser through WebAssembly, using pdf-lib, pdfjs-dist and tesseract.js, so a contract, a medical record or a court exhibit is read into memory on your own machine and never transmitted anywhere. That constraint is the reason the tools work the way they do, and it shapes the advice in these guides — particularly the parts about redaction, metadata and hidden data, where the difference between hiding something and removing it is the difference between a safe document and a disclosure.

The guides are written from building the tools: the failure modes described in them are the ones that turn up in the PDF specification and in real files — OCR text layers surviving under a black box, stamped page numbers that do not recalculate, fonts that cannot be embedded for PDF/A. Corrections and suggestions are welcome.