FS PDF Compressor

FS = Fast & Simple: free, private PDF compression for Mac, Windows, and Linux. Drag, drop, done.

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FS PDF Compressor — Fast & Simple PDF Compressor — is a deliberately small, free PDF compressor for Mac, Windows, and Linux. It compresses PDFs locally with Ghostscript, so you can compress PDF files without uploading them to a website. It is a private, open-source PDF compressor for Apple Silicon Macs and x86_64 Linux, with a self-contained AppImage for Linux users and a Windows x64 installer.

Features

• Drag and drop one PDF, several PDFs, or a folder.
• Send selected PDFs from Finder, Windows Explorer, GNOME Files, or KDE Dolphin.
• Balanced compression by default, with Preserve, Maximum, and an optional Smart scans profile for high-resolution black-and-white documents.
• Smart scans converts only high-confidence, page-sized monochrome document images to 1-bit encoding. It changes selected scans through downsampling and thresholding; colour marks, masks/transparency, native text, vectors, and uncertain images remain unchanged.
• Smart scans checks local contrast and connected faint marks before conversion. Coherent JPEG ringing is also uncertain content and can trigger Balanced fallback, so some JPEG scans get no additional size saving. Isolated one-pixel speckles are ignored; this remains a lossy profile, not a fidelity guarantee.
• Replaces the original only when the result is smaller.
• Optional Keep original mode creates a separate compressed copy and remembers your choice between app launches.
• Processes everything locally: no uploads, accounts, analytics or telemetry.
• Includes Ghostscript, so end users do not need Homebrew or a separate install.
• macOS distribution is Developer ID signed and notarized by Apple.

Drop Zone

Drop Zone is an optional shortcut for compressing PDFs without reopening the main window. It gives FS PDF Compressor a little personality while keeping the workflow fast: leave the small target on the desktop and drop PDFs onto it whenever they need to be compressed. Double-click it to reopen the main window.

• On macOS, choose FS PDF Compressor → Show Drop Zone. The Drop Zone is available in every Space (virtual desktop). Uncheck the same menu item to hide and disable it. Launch at Login in the same menu is optional.
• On Linux, choose Application → Show Drop Zone and uncheck it to hide and disable it. X11 desktops can keep it at desktop level. Under Wayland, the compositor controls window placement and stacking, so the app cannot reliably pin it to the desktop layer; it may appear as a normal floating utility. We are investigating better Wayland integration.
• On Windows, the Drop Zone is shown on first launch. Closing the main window leaves it available; double-click it to reopen the app.

The setting and position are remembered. Drop Zone stays idle without polling the filesystem and uses the same local compression engine and selected quality profile as the main window.

File-manager actions

• On macOS, select one or more PDFs in Finder and choose Quick Actions → Compress with FS PDF Compressor. If it is hidden after installation, open Quick Actions → Customize… once and enable it under Finder extensions.
• On GNOME Files, the per-user AppImage installer adds Compress with FS PDF Compressor to the Scripts submenu.
• On KDE Dolphin, the per-user AppImage installer adds Compress with FS PDF Compressor to the Actions submenu for PDF files.
• On Windows, select PDFs in Explorer and choose Compress with FS PDF Compressor. Windows 11 may place this classic per-user action under Show more options.

All three actions pass the selected files to the same local compression flow; no document is uploaded.

Download

• macOS 14+ on Apple Silicon: download the signed and notarized DMG.
• Linux x86_64: install from the Snap Store for automatic updates, or download the self-contained AppImage.
• Windows 11 x64: download the per-user installer or the portable ZIP.

The macOS build is Developer ID signed and Apple-notarized, so it opens normally with Gatekeeper enabled. The Linux AppImage is portable and bundles Ghostscript; make it executable and run it, or use the per-user installer:

curl -fsSLO https://raw.githubusercontent.com/gitlares/fs-pdf-compressor/main/scripts/install_linux_appimage.sh
sh install_linux_appimage.sh

The installer needs no sudo. It verifies the published SHA-256 checksum, adds FS PDF Compressor to the applications menu, and keeps the AppImage in a user-writable location so in-app updates can replace it safely.

The Windows installer includes its dependencies and needs no administrator rights. It is currently unsigned, so verify the matching published SHA-256 checksum before installing it. Windows updates are manual for now: download a new installer from the official GitHub release when one is published.

See what changed in 1.0.16 or read the complete changelog.

Build from source

macOS

Requirements: Apple Silicon Mac, macOS 14+, Homebrew and Python 3.12.

brew install python@3.12 ghostscript
python3.12 -m venv .build-venv
.build-venv/bin/python -m pip install -r requirements-build.txt
.build-venv/bin/python build_macos.py

The app and DMG are written to release/. The build bundles Ghostscript and its non-system dynamic libraries, copies detected license files, and rewrites their Mach-O paths. Local builds use an ad-hoc signature unless a Developer ID identity is supplied; see the release guide for the notarized distribution workflow.

Linux

The Linux edition is developed in this same repository. It uses the same compression engine and profiles, with a Qt interface designed to match the macOS app. The x86_64 AppImage bundles Ghostscript and has an in-app update check; see Linux instructions.

Windows

The Windows edition uses the shared Qt interface and can be built from source as an x86_64 per-user installer. See the Windows build and test instructions. The public installer and its portable ZIP are available from the 1.0.16 release.

Code structure

The application keeps compression behavior independent from its interfaces:

• fs_pdf_compressor/core.py owns PDF discovery, Ghostscript execution and output-file safety.
• fs_pdf_compressor/batch.py owns platform-neutral batch summaries.
• native_app.py and the macos_* modules provide the AppKit application.
• linux_app.py and the linux_* modules provide the Qt application and AppImage update flow.
• windows_app.py and linux_app.py provide the shared Qt application for Windows and Linux; native_app.py provides the macOS application.
• build_macos.py, build_linux.py, and build_windows.py package the same source for their respective platforms.

Acknowledgements

The Linux edition is distributed as an AppImage. Thank you to Simon Peter and the AppImage project for a philosophy that fits this application: less software around the task, but a well-made, portable tool that users can simply download and run.

Contributing

Issues, translations, accessibility improvements and focused pull requests are welcome. Read CONTRIBUTING.md before submitting changes. If the app is useful to you, starring and sharing the repository also helps.

Support the project

If FS PDF Compressor saves you time, you can support its continued development with an optional PayPal donation. The app remains free and open source for everyone.

Privacy

PDFs never leave your computer. Network access is limited to documented update delivery and links opened by the user; see the short privacy statement.

License

FS PDF Compressor is released under the GNU Affero General Public License v3.0 or later. Version 1.0.16 bundles Ghostscript 10.07.1 under the AGPL and other open-source libraries; see THIRD_PARTY_NOTICES.md.

Copyright © 2026 Daniel Lares.

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