Open-Source PDF Editors 2026: 8 Best Free Tools

1. Stirling PDF - the open-source Adobe Acrobat

Stirling PDF is the closest thing to a self-hosted Adobe Acrobat. It is a web application that bundles 50+ PDF tools: merge, split, OCR, sign, compress, rotate, password-protect, edit metadata, redact, fill forms, convert formats, and more, all driven from a clean browser UI and a REST API for automation. You run it yourself, so nothing leaves your network. The fastest way to try it is Docker:

docker run -p 8080:8080 docker.stirlingpdf.com/stirlingtools/stirling-pdf

Then open http://localhost:8080. With roughly 85k GitHub stars it is the most-starred PDF application on GitHub, and it is MIT-licensed (the project relicensed to MIT, so it is genuinely permissive). Best for IT teams, MSPs and anyone who wants Acrobat-grade page operations without the subscription. It pairs naturally with our other free browser-based IT tools.

2. ONLYOFFICE PDF Editor - real content editing and collaboration

ONLYOFFICE is the pick when you need to change the actual content of a PDF, not just rearrange it. Its PDF editor lets you edit text and images directly on the page, add annotations and comments, build and fill interactive forms, sign documents, and collaborate with others in real time. It ships as a free desktop app (Windows, Linux, macOS) and as a web editor you can self-host alongside the wider ONLYOFFICE document suite. The desktop editors repo sits at around 5k GitHub stars and is licensed AGPL-3.0. Best for users who treat a PDF like an editable document, and for teams that want collaborative review and form workflows in one open-source package.

3. LibreOffice Draw - free PDF editing on any OS

If ONLYOFFICE is more than you need, LibreOffice Draw is the default fallback that millions already have installed. It opens PDFs directly and lets you edit text boxes, move and replace images, and re-export, all completely free and cross-platform across Windows, Linux and macOS. The trade-off is layout fidelity: because Draw reconstructs the PDF as editable objects, complex multi-column or heavily designed layouts can shift when you edit them. The LibreOffice source lives on the project's own infrastructure; the read-only GitHub mirror (LibreOffice/core) shows around 4.1k stars, and the suite is licensed under the Mozilla Public License 2.0. Best for occasional, light PDF text edits where you already run LibreOffice.

4. PDF Arranger - reorganise pages in seconds

PDF Arranger does one job and does it well: visual page management. It is a small Python/GTK app that lets you merge documents, split them, and rotate, crop, delete, duplicate and rearrange pages by dragging thumbnails around an intuitive grid. You can also extract selected pages into a new file. There is no text editing here, and that is the point: it stays fast and obvious. The repo (pdfarranger/pdfarranger) has roughly 5.6k GitHub stars and is GPL-3.0 licensed. Best for anyone who regularly assembles, reorders or trims PDFs and wants a lightweight, no-learning-curve tool to do it.

5. Okular - the power-user reader with annotations

Okular is KDE's universal document viewer, and it is an outstanding PDF reader with serious markup features. On top of fast, polished reading it supports annotations, inline comments, highlights, digital signatures, and filling in PDF forms. What it does not do is true content editing: you cannot rewrite the underlying text or reflow the layout. The canonical code lives on KDE infrastructure; the GitHub mirror (KDE/okular) shows around 1.4k stars, and it is licensed GPL-2.0-or-later. Available across Linux, Windows and macOS. Best for people who mainly read and review PDFs (academics, reviewers, anyone marking up documents) and want annotations and signatures without a heavyweight editor.

6. Xournal++ - stylus, handwriting and signatures

Xournal++ is a handwriting and note-taking application with first-class PDF annotation. If you have a pen-enabled device or a Wacom tablet, it shines: you can write directly on top of a PDF, add typed text, highlight, draw shapes, and drop in a handwritten signature. It is genuinely cross-platform (Linux, Windows, macOS) and supports proper pressure-sensitive pen input. With roughly 15k GitHub stars (xournalpp/xournalpp) it is one of the most popular tools on this list, and it is GPL-2.0 licensed. Best for students, note-takers and anyone who wants to sign or mark up documents by hand rather than with form fields.

7. Inkscape - edit vector graphics inside a PDF

Inkscape is a professional vector graphics editor, and it has a niche but valuable PDF role: editing the vector content of a page. When a PDF contains a logo, diagram, chart or line-art drawing, Inkscape can import the page, let you edit those vector objects precisely, and export back to PDF. It is the wrong tool for multi-page office documents or body text, but the right one for graphics. The canonical project lives on GitLab; the GitHub mirror (inkscape/inkscape) shows around 3.6k stars, and Inkscape is licensed GPL-2.0-or-later. Best for designers and technical authors who need to fix or redraw a vector element that lives inside a PDF.

8. PDFsam Basic - the veteran merge/split tool

PDFsam Basic (PDF Split and Merge) is one of the oldest open-source PDF projects still going strong. The free Basic edition focuses on the core manipulation tasks: merge multiple PDFs, split one into several, rotate pages, extract specific pages, and mix documents together. It is a desktop Java application that runs on Windows, Linux and macOS. The repo (torakiki/pdfsam) sits at around 4.5k GitHub stars and is AGPL-3.0 licensed. Best for users who want a stable, long-trusted desktop tool purely for combining and dividing PDFs, and who prefer a dedicated app over a web UI.

How to choose the right open-source PDF editor

Match the tool to the task rather than hunting for a single do-everything app:

• Manipulate pages (merge, split, rotate, extract): Stirling PDF for the full self-hosted toolkit, or PDF Arranger / PDFsam Basic for a focused desktop app.
• Edit text, images and forms inside the document: ONLYOFFICE PDF Editor for true content editing and collaboration; LibreOffice Draw for quick, free edits you already have installed.
• Annotate, comment, highlight or sign: Okular for mouse-and-keyboard markup and signatures; Xournal++ when you have a stylus or tablet and want to write by hand.
• Edit vector graphics (logos, diagrams, drawings): Inkscape, exporting back to PDF.
• OCR, redaction, compression, passwords, metadata and an automation API: Stirling PDF covers all of these in one place, which is why it tops the list.

For organisations, the bigger win is combining a PDF toolkit with a document workflow. Pairing Stirling PDF with the Paperless-ngx document management spotlight gives you a self-hosted pipeline that scans, OCRs, organises and edits documents without any of it touching a third-party cloud. For one-off conversions and quick fixes in the browser, our free browser-based IT tools cover the gaps. Whatever you pick, every option here is free and open-source: you get Acrobat-class capability, keep your documents private, and drop the subscription.