Fully featured
- Four view modes across unlimited tabs
- Text, highlights, drawing and shapes
- Edit text inline and OCR scans
- Fill and sign PDF forms
- Stamp page numbers and watermarks
- Crop, transform, merge and split
- Print with full control, or flatten
Built from scratch
KillerPDF is written in C# and WPF on .NET. It renders through PDFium and runs OCR on Tesseract, with extra language models downloaded only on demand so the base download stays small.
A few focused libraries handle the rest, so the whole app stays one lean native exe with no bundled browser engine. The Technical page has the full breakdown.
The people's editor
Much of what KillerPDF does was requested by the people who use it. The GitHub issues page is open to anyone, so anybody can request a feature or report a bug.
Your suggestions genuinely shape where this goes next. Read the story behind the app on the About page.
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Install or run portable. No account. No subscription. No telemetry. No ads. Free, open source, GPLv3.
Built by a field tech with an intense dislike for Adobe.
What it does
View & navigate
PDFium rendering with four view modes - single page, continuous scroll, two-page, and a grid of every page. Open several PDFs in tabs, with search, outlines, and clickable links.
Annotate & edit
Inline text editing with font matching, plus text boxes, freehand drawing, a line tool, and highlights - each with its own color, opacity, and width. A full RGB color picker on every swatch.
OCR built in
OCR a page or a dragged region to the clipboard, make a scanned PDF searchable, or extract all text to a file. Tesseract ships in the exe; extra languages download on demand.
Organize pages
Merge PDFs and split out pages, drag to reorder, rotate, extract, and stamp page numbers. Drop a folder or .zip to merge everything inside into one PDF or open each separately.
Forms & signing
Fill PDF forms and save them back. Draw reusable signatures, or sign with a cloud certificate (Certum SimplySign) and click-to-sign form fields.
Transform
Rotate, scale, flip, and straighten a crooked scan by drawing a level line - all with a live preview, and annotations follow the page.
Print & flatten
A real in-app print preview with scale, position, margins, pages-per-sheet, color, and two-sided options, rendered at 300 DPI. Or save a flattened, fully uneditable copy.
Themes & languages
Six themes with per-theme accent colors, switchable live, plus a left-or-right resizable sidebar. UI localized in eight languages.
Document info
View and edit a PDF's title, author, subject, keywords, and creator metadata, saved back into the file.
Stamps & watermarks
Stamp page numbers or a text watermark across any page range - positioned, sized, and styled - applied as a single undo.
Opens anything
Opens password-protected PDFs by prompting instead of erroring, and repairs damaged or broken-xref files so they open and print.
Install or run portable
Drop the exe anywhere and run it, or use the built-in per-user installer with no admin rights. You can also grab it from the command line:winget install killerpdf