TorReader PDF

TorReader is a lightweight, portable PDF app for Windows and Linux — a fast PDF viewer that also handles the everyday jobs quickly: merge, extract, split, and insert pages, sign PDFs digitally, and translate PDFs for free. Everything runs locally on your machine, with no installation required — unzip (or chmod +x) and run.

Open a 900MB PDF in a second or two, combine files without losing bookmarks, pull out or split pages, insert pages from another PDF, add a digital signature, and translate text in place — free and open-source (MIT).

🚀 Built for large, multi-hundred-page drawing sets

TorReader stays smooth on the files that make other viewers crawl — a 300-page A1 CAD drawing set opens fast, scrolls and pages without freezing, and keeps memory low. The renderer draws each page in short, interruptible slices so the UI never blocks, backs it with a two-layer (memory + disk) cache, and evicts off-screen pages so RAM stays flat no matter how many pages you flip through.

⬇ Download

Platform	Install
Windows (x64)	TorReaderPDF-2.3.0-win64.zip — unzip & run TorReader.exe
Ubuntu / Debian (APT repo)	sudo mkdir -p /etc/apt/keyrings sudo curl -fsSL https://torreader.cloud/apt/torreader-archive-keyring.gpg -o /etc/apt/keyrings/torreader.gpg echo "deb [signed-by=/etc/apt/keyrings/torreader.gpg] https://torreader.cloud/apt stable main" | sudo tee /etc/apt/sources.list.d/torreader.list sudo apt update && sudo apt install torreader → auto-updates via apt upgrade
Ubuntu / Debian (standalone .deb)	Download .deb from Releases & run: sudo apt install ./torreader_2.3.0_amd64.deb
Arch Linux	yay -S torreader-bin (pending publication on AUR)
Any distro (AppImage)	TorReaderPDF-2.3.0-x86_64.AppImage — chmod +x & run (glibc 2.35+, Ubuntu 22.04+; requires system OpenGL)

The app ships a freedesktop-compatible .desktop file and AppStream metadata, so it appears in your application menu and "Open with" for PDF files.

See all versions on the Releases page.

✨ What's new in 2.3

• Instant sharpness on heavy CAD drawings. The page's vector geometry is uploaded to the GPU and drawn directly, so zooming and panning are sharp immediately instead of waiting for a re-render. On a 2.18-million-path drawing, a viewport re-render costs ~2 seconds and does not get cheaper at lower resolution — the GPU draws it at once.
• GPU rendering in Continuous scroll too — the same VectorGpuRenderer layer is shared with the single-page view, so scrolling through heavy pages no longer re-rasterises them. Markups in Continuous are display-only (with popups); to select or edit markup, switch to single-page view.
• True line weights and dashes. Stroke widths, dash patterns, fills and clipping are respected, so drawings keep their line hierarchy instead of coming out as uniform hairlines.
• Text stays exact. Text is rendered with the document's own embedded fonts, so accented scripts — including Vietnamese — are correct at any zoom.
• A comment on every markup. Line, arrow, rectangle, ellipse, cloud, freehand and highlight all carry popup text now. Type it inline in the Comments list (p.4 Arrow — …), see it as a popup when you select the markup, with full undo/redo.
• Fit Page centres the page; Translate region select moved to Alt+drag (Ctrl+drag was colliding with zoom); larger undo/redo buttons; Share app button with a copyable download link.

Full release notes: RELEASE_NOTES_2.3.md

More screenshots (viewer, dark mode, markup, digital signature, merge)

Features

• Fast PDF viewer, built for large drawing sets — memory-mapped loading opens 900MB files in 1–2s; 300-page A1 CAD sets scroll and page without freezing thanks to progressive interruptible rendering + a two-layer cache; continuous scroll is RAM-efficient (off-screen pages evicted), sharp at every zoom even with mixed page sizes (A4 + A0–A3 in one file)
• Merge PDF — combine files while keeping every bookmark, remapped to the new page numbers (most tools drop them); unbookmarked pages get an auto "Page N" entry
• Split PDF — split a document into parts by page count or size
• Extract pages — pull any page or range out into a new PDF
• Insert pages — Adobe-style, right-click a thumbnail to insert pages from another PDF; bookmarks renumber to match
• Sign PDF — digital signature, PKCS#7 detached, SHA-256, using your own .pfx/.p12 certificate; optional visible signature stamp, placed by dragging then confirmed with "Finalize Signature"
• Comments (markup) — Line, Arrow, Rectangle, Ellipse, Cloud, Text box, and sticky Note tools with colour/width/fill controls; select, move, and undo/redo any markup. Text boxes support adjustable font size and colour (right-click → Properties), and all markup lands correctly on rotated pages
• Translate PDF (free) — Ctrl+drag over text to translate it in place, cached locally
• Delete / Reorder pages, reorder bookmarks
• Dark mode, full keyboard shortcuts (press F1 in-app for the full list)
• Safe save model — edits (insert/delete/reorder/merge) apply to an in-memory working copy first; your original file is only overwritten when you press Ctrl+S

How it compares

An objective look at 24 PDF apps — paid suites, open-source desktop viewers, self-hosted toolkits and web tools — across 11 everyday jobs. Tools are sorted A–Z within each group; TorReader is listed in its category, not on a pedestal.

_{● full support · ◐ partial, limited or paid-tier only · ○ not available. General positioning as of 2026 — feature sets vary by version and licence tier; verify the current release before deciding.}

FAQ

Is TorReader free? Yes — free and open-source (MIT). No ads, no account, no watermark.

Do I need to install it? No. It's a portable app: on Windows, unzip and run TorReader.exe; on Linux, chmod +x the AppImage and run it.

Does it work offline? Yes — all PDF viewing and editing (merge, split, extract, insert, sign) happens locally on your machine. Only the optional translate feature calls an online translation service when you use it.

Can it merge PDFs without losing bookmarks? Yes. Merging (and inserting pages) keeps every bookmark and remaps it to the new page numbers — a common problem with other free tools.

What platforms are supported? Windows 10/11 (x64) and Linux (x86_64, AppImage).

Is it a free alternative to Adobe Acrobat, PDFsam or Foxit? For viewing, merging, splitting, extracting, inserting, signing and translating PDFs — yes, TorReader covers those jobs in a single lightweight, portable app.

Building from source

Requirements (both platforms)

• CMake ≥ 3.25
• Qt 6 (Core, Widgets, Gui, Concurrent, PrintSupport, OpenGL, OpenGLWidgets, Network)
• QPDF ≥ 11 (dev headers)
• PDFium prebuilt binaries — download from bblanchon/pdfium-binaries releases and extract into third_party/pdfium/ (must contain include/, lib/, and on Windows bin/pdfium.dll)
• (optional) OpenSSL dev headers — enables the "Sign PDF" feature. Skipped cleanly if not found.
• (optional) Tesseract OCR dev headers — enables OCR search on scanned pages.

Windows

# Requires Visual Studio Build Tools 2022 + vcpkg (for QPDF/OpenSSL)
vcpkg install qpdf openssl
cmake -B build -DCMAKE_TOOLCHAIN_FILE=C:/vcpkg/scripts/buildsystems/vcpkg.cmake
cmake --build build --config Release
# → build/bin/Release/TorReader.exe

Linux

# Debian/Ubuntu example
sudo apt install cmake qt6-base-dev libqt6opengl6-dev libqt6openglwidgets6 \
                  libqpdf-dev liblcms2-dev libssl-dev
cmake -B build
cmake --build build -j$(nproc)
# → build/bin/TorReader

Building without libssl-dev installed works fine — the Sign PDF feature is simply disabled at configure time (see the CMake status message).

Architecture

• Rendering & structural editing: PDFium (BSD 3-Clause) — merge, split, insert, extract, reorder, rotate all go through FPDF_ImportPagesByIndex and friends.
• Bookmark/outline writing + compression: QPDF (Apache-2.0) — object-stream compression on save, lossless.
• UI: Qt 6 Widgets + OpenGL (PdfGpuView single-page view, ContinuousView scroll strip).
• Thumbnails & previews: rendered by PDFium through a shared render pool; the main view always uses PDFium for full-resolution, correctly laid-out rendering.
• All FPDF_* calls are serialized behind a global mutex — PDFium is not thread-safe.

See THIRD_PARTY_NOTICES.md for the full list of dependencies and their licenses.

License

TorReader's own source code is MIT-licensed. Third-party dependencies keep their own licenses — see THIRD_PARTY_NOTICES.md.

Author

Built by Felix Nguyen Huy (@FelixNgH).

• Web: torreader.cloud
• Also building: BIMServer.cloud — BIM infrastructure for architecture firms
• Twitter: @FelixNgHuy

Issues and pull requests welcome.