View, annotate, edit, merge, split, sign (drawn or cryptographic), fill forms, OCR, watermark, transform, redact, and protect PDFs — without an Adobe subscription, an account, or a single network call. One self-contained ~6 MB EXE. Install it or run it portable. No telemetry, no phone-home. GPLv3.
The PDF equivalent of Notepad.
Website: https://scalpel-pdf.netlify.app · Microsoft Store: https://apps.microsoft.com/detail/9n9hn8xw4lf3
Acrobat is bloated, hijacks file associations, wants a subscription for basics, and phones home constantly. Most "free" alternatives are ad-riddled, cloud-based, or the same PDF engine rebranded three times over.
Scalpel is the opposite: everything runs on your machine. Files are opened, edited, and saved locally — nothing is uploaded, there's no account, and there's no telemetry. Even OCR runs offline on your CPU.
The "Clinical" ribbon interface — organized into View · Edit · Pages · Sign tabs, in light and dark.
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| View (Light / Clinical) | Edit (Dark) |
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| Pages organize | Grid view (Green accent) |
Edit & annotate
- Inline text editing with font matching against the original document; right-to-left scripts (Hebrew/Arabic) shape and read correctly
- Text boxes, freehand ink, straight lines (Shift to snap), and highlight overlays with adjustable size and opacity
- A full color picker with eyedropper (RGB/hex, or sample any pixel on screen) for the Draw, Line, and Text tools
- Insert images as resizable annotations; crop pages with drag handles — all burned cleanly into the PDF on save
Pages
- Merge multiple PDFs, split out selected pages, drag-and-drop reordering
- Right-click sidebar: insert blank page, rotate, move, extract, or delete — on multi-page selections
Sign & forms
- Draw and save reusable signatures (chosen from a dropdown under the Sign button), or import a PNG/JPG/BMP and click to place
- Add a real cryptographic signature with your own certificate (see Digitally sign in the Tools menu below)
- Fill interactive PDF forms (text fields, checkboxes, radio buttons) and save back to the PDF — fields render correctly on cropped PDFs and in every view mode
Tools menu — document operations, run locally
- Page & Bates numbering with corner headers/footers
- Watermark & image stamp — a semi-transparent text watermark (rotated, tiled, any opacity) and/or a logo image placed on every page
- Transform pages — rotate in 90° steps, fine-deskew, scale, and flip horizontal/vertical (lossless for plain rotation)
- Compression (Low / Medium / High image down-sampling)
- OCR — make scans searchable with a bundled, offline Tesseract engine (portable builds fetch language data once, on demand); live per-page progress with cancel, a language picker, a high-quality mode, copy-page-text to clipboard, extract-all-text to
.txt/.md, and OCR a dragged region straight to the clipboard - Digitally sign (PKI) — add a real cryptographic signature (PAdES / PKCS#7 detached) with your own
.pfx/.p12certificate or a certificate from the Windows certificate store (smart cards, enterprise certs), appended via incremental update so the signed copy stays valid in PDF readers. Options: a trusted RFC-3161 timestamp (stays valid after the cert expires), a visible signature box in a page corner, and embedded long-term validation (LTV) info — distinct from the drawn signatures above - Redaction — permanently remove content (pixels gone, not just hidden)
- Password protection — encrypt with a password and set viewing/editing permissions
- Metadata removal — strip author, timestamps, and hidden data before sharing
View & navigate
- Document tabs — open several PDFs and switch between them from a tab strip (Ctrl+Tab to cycle)
- Recent files — reopen a recent PDF from the start screen or the Open button's menu
- Single-page, continuous scroll, two-page, and grid view modes (persisted across sessions), plus full-screen (F11)
- High-quality PDFium rendering, with damaged-file recovery
- Outline/bookmark navigation, clickable links and cross-references, full-text search with highlighting, zoom presets with scroll-wheel sync, page-jump box, keyboard shortcuts (Ctrl+?)
Output
- Print with annotations flattened in
- Save a flattened (uneditable) copy
- Open password-protected PDFs (prompts instead of erroring)
Themes & languages
- Three base themes — Light, Dark, High Contrast — each with Amber / Red / Green / Cyan accents. The default is the Light + Red "Clinical" look. Switch live in Settings.
- 9 interface languages: English, Spanish, Traditional & Simplified Chinese, Bengali, Turkish, Hebrew, Arabic, and Russian — with a fully mirrored right-to-left UI for Hebrew and Arabic. Contribute one via
Strings/TRANSLATING.md.
Privacy & updates
- 100% on-device. No account, no telemetry, no phone-home.
- Optional, opt-in update notifications (off until you enable them; checks a single static file, sends nothing about you).
- Microsoft Store (auto-updating, sandboxed): https://apps.microsoft.com/detail/9n9hn8xw4lf3
- Website (portable + installer): https://scalpel-pdf.netlify.app
- Direct EXE (latest release): https://github.com/blakazulu/ScalpelPDF/releases/latest
The portable EXE and the installer are the same file — run it in place to stay portable, or click Install and it sets itself up per-user in %LOCALAPPDATA% (no UAC), registers as the .pdf handler, adds shortcuts, and uninstalls cleanly via Add/Remove Programs. Web-downloaded builds are unsigned, so Windows SmartScreen may warn on first run (More info → Run anyway); the Store build is fully managed by Windows.
- Windows 10 or 11 (x64)
- No runtime install — everything is inside the EXE (targets .NET Framework 4.8, which ships with every supported Windows release)
git clone https://github.com/blakazulu/ScalpelPDF.git
cd ScalpelPDF
dotnet publish -c ReleaseOutput lands in bin/Release/net48/publish/ as a single Costura-bundled Scalpel.exe, plus a versioned Scalpel-<version>-src.zip (GPLv3 corresponding source).
- Targets .NET Framework 4.8 but requires the .NET 8 SDK or later to build. Output is x64.
dotnet testruns the xUnit suite (Scalpel.Tests).release.ps1is the full signed-release pipeline (build → Authenticode sign → verify → hash). Ordinary dev builds don't need it.
The same Scalpel.exe can be wrapped into an MSIX. When run from a package, the app detects MSIX and disables its self-installer — the OS/package owns install, uninstall, and the .pdf association. Build a local sideload test package with:
pwsh -File packaging\build-msix.ps1 -SelfSignSee docs/STORE-PUBLISHING.md for sideload testing and Store submission (including the GPLv3-on-the-Store licensing note).
docs/OVERVIEW.md— full architecture and what-it-does referencedocs/system-design.md— the "Clinical" ribbon design system (layout, themes, components, brand assets)docs/UI-REFERENCE.md— every control mapped to its handlerdocs/STORE-PUBLISHING.md— MSIX build + Store submission
See CHANGELOG.md, or the in-app What's New popup.
GPLv3. See LICENSE. If you fork, modify, or redistribute Scalpel, your version must also be released under GPLv3 with source available. No exceptions for commercial rebrands.
Website rule: native, site-matched cross-browser scrollbars are required on every new site. Floating privacy preferences hide five seconds after opt-in; the privacy policy keeps a permanent reopen control (2026-10-01).