A small, fast, native PDF reader and annotator for Windows. No installer, no account, no telemetry — two files in a folder, about 4 MB.
Free to use for any purpose, personal or commercial, on as many machines as you like. See LICENSE.
Read — multi-page scrolling with momentum, zoom to cursor, fit width/height/page, page thumbnails, document outline, find, and tabs for several documents at once.
Annotate — highlight, strikethrough, sticky notes, rectangles, ellipses, lines, free text, and signatures (drawn freehand or from an image). Everything you place can be selected, moved, resized, restyled or deleted, with undo.
Review — attach a comment to a highlight or strikethrough, and open a column beside the page that lists every note level with the text it marks.
Fill forms — type into AcroForm fields, copy out of them, and save.
Redact — properly. The covered text is removed from the file, not painted over, so it cannot be recovered by selecting or extracting.
Manage pages — rotate, delete, reorder by dragging, insert blank pages or pages from another PDF, extract a selection to a new file.
Plus printing with preview, save flattened or compressed, and four themes.
Unzip anywhere and run OnyxPDF.exe. Keep pdfium.dll beside it. There is no
installer, nothing is written to the registry, and no admin rights are needed —
a USB stick works fine. To uninstall, delete the folder (settings live in
%APPDATA%\onyxprojects).
Requirements: Windows 10 or 11, 64-bit. No Visual C++ redistributable — the runtime is linked statically.
The download is not code-signed, so SmartScreen warns the first time you run it. Click More info, then Run anyway; Windows remembers the choice.
If you would rather check before trusting it, each release lists the SHA-256 of its zip. Verify with:
Get-FileHash OnyxPDF-0.1.0-win-x64.zip -Algorithm SHA256PDFium for rendering, forms and annotations (BSD 3-Clause), FLTK for the interface (LGPL v2 with a static-linking exception), and stb for image decoding (public domain). Full notices are in the app under Help → Third-Party Libraries.
Open an issue — what you did, what happened, and the PDF if you can share it.
This repository holds releases only; the source is not published.