PDF4QT — The Complete Guide: An Open PDF Editor With Annotations, Signing and Version Comparison
PDF4QT is an open-source (MIT) PDF suite that covers most of what an engineering office does with PDFs on a normal day: reading and annotating, merging and splitting, signing, redacting sensitive information and comparing versions.
PDF4QT
Jakub Melka
An open PDF editor and viewer — annotations, page organising, signing, redaction, plus a tool to compare document versions.
Get it from the vendorWhat you get
- Advanced viewer — annotation editing, regular-expression search and signature verification.
- Page organiser — merge and split files.
- Document comparison — a detailed report of the differences between two files.
- Signing and redaction — digital signatures and hiding information before sending.
- Extras — compression, text-to-speech and a separate lightweight viewer.
Who it suits
Anyone looking for a free alternative to a commercial PDF editor, including for commercial work and with no licence key. PDF4QT runs on Windows and Linux only — there is no macOS version.
Related tools
For viewing and signatures on Linux — Okular. For batch splitting and merging — PDFsam Basic. For overlay-style visual comparison — diff-pdf.
Okular
KDE
KDE’s document viewer — read and annotate PDFs with highlights and notes, and verify digital signatures.
Get it from the vendor
PDFsam Basic
Sober Lemur
Split, merge, rotate and extract PDF pages — for drawing sets, specifications and submissions.
Get it from the vendordiff-pdf
Vaclav Slavik
Visual comparison of two PDF versions — see at once what changed between revisions of a drawing or report.
Get it from the vendor
SumatraPDF
Krzysztof Kowalczyk
A tiny, very fast PDF reader for Windows — opens heavy drawings instantly, and reads ePub and DjVu too.
Get it from the vendorThe bottom line
PDF4QT gathers many tools into one suite, and in an office that works on Windows it can replace quite a few paid licences.