Stirling-PDF: The Self-Hosted PDF Suite That Replaces Adobe Acrobat

If you're paying for Adobe Acrobat Pro because your team needs to merge contracts, redact sensitive fields, convert files between formats, or add digital signatures, Stirling-PDF covers all of that. It runs entirely on your own computer or server, processes files locally, and deletes them automatically when it's done. No subscription. No files uploaded to a cloud you don't control.

The project sits at github.com/Stirling-Tools/Stirling-PDF with 88,000+ GitHub stars, making it one of the most-starred PDF tools in existence. Version 2.14.2 shipped in July 2026.

What Stirling-PDF actually is

Stirling-PDF is a web-based PDF editing platform you run yourself. "Self-hosted" means the software lives on your computer or a server your organization controls, not on someone else's infrastructure. When you upload a PDF to work on it, that file goes to your machine, not to Adobe's servers, Google's servers, or anyone else's. The app processes the file and deletes it when the task is done.

The interface looks like a web app and works in any browser. If you deploy it on a company server, everyone on the team gets the same URL and the same set of tools. If you install the desktop version, it's a standalone application on your laptop.

The tool count is 60+, organized into categories: editing, merging and splitting, signing and certification, redaction, format conversion, OCR (text recognition that lets you search and copy text from scanned documents), and compression. There's also an automation layer that lets you chain operations together without writing any code.

The project uses an open-core model, which means the core software is free and open-source, while certain advanced team or enterprise features are available on paid plans. The core PDF tools are free and open-source. Team features like SSO (single sign-on, which lets employees log in with their existing company credentials instead of a separate password) and external database support sit behind a paid Server Plan at $99 per month. For a solo user or a small team that just needs the PDF tools themselves, the free version is fully capable.

What you get after installing it

The homepage after install is a clean grid of tool cards. You click a card, upload your file, set your options, and download the result. There's no account required, no trial watermark, and no feature gating on the PDF operations themselves.

Editing and page management

You can reorder pages by dragging thumbnails, delete individual pages, rotate, crop, add page numbers, add headers and footers, and insert blank pages anywhere in a document. Multi-file merge lets you drag in several PDFs and specify exactly how they should be combined.

Signing and redaction

Digital signatures work through the browser interface without external software. Redaction is a distinct tool: you draw boxes over text or images to permanently black them out, not just visually cover them. For legal teams preparing documents for discovery (the process of sharing evidence and documents with opposing counsel before a trial or proceeding), that distinction matters.

Format conversion

PDF to Word, PDF to Excel, PDF to image, image to PDF, HTML to PDF, PowerPoint to PDF, and more. OCR (again: the technology that reads text from scanned documents and makes it searchable and copyable) is built in and applied automatically when you convert a scanned PDF. The full-fat Docker image includes LibreOffice (a free office suite) and Tesseract (the OCR engine) pre-installed so conversions work out of the box.

Automation and pipelines

There's a no-code pipeline builder in the interface. You pick a sequence of operations, configure each one, and save it as a named workflow you can re-run. An organization that processes the same type of document repeatedly, such as weekly invoice PDFs that need to be compressed and renamed, can set that up once and run it without manual steps. A REST API (an interface that lets other software call Stirling-PDF's tools automatically) is available for nearly all operations, which matters if your IT team wants to wire it into an existing document workflow.

Multi-user and enterprise features (paid)

On the free tier, up to five users can have accounts. The Server Plan removes that cap for $99/month flat, with no per-seat charges regardless of team size. The Enterprise plan adds SSO, audit logs, and a dedicated support contact.

The install experience

Docker is a tool that packages software into a self-contained bundle (called a container) you can run on any computer without a complex manual setup. If Docker is installed on your machine, one terminal command starts the full Stirling-PDF server:

docker run -d -p 8080:8080 -v ./stirling-data:/configs stirlingtools/stirling-pdf:latest

That single command downloads the application and starts it. Then you open http://localhost:8080 in a browser and you're in the app.

For teams that want all the conversion features, the "fat" variant pre-installs LibreOffice and Tesseract:

docker run -d -p 8080:8080 -v ./stirling-data:/configs stirlingtools/stirling-pdf:latest-fat

Desktop app (no command line required)

If you want to skip Docker entirely, Stirling-PDF ships a native desktop application for Windows, macOS, and Linux. Download the installer from docs.stirlingpdf.com, run it, and the app opens in your default browser against a local server it manages itself. No terminal, no Java to install, nothing extra to configure. The desktop app is the right choice for individual use.

Manual server install

If your organization can't run Docker, the manual path requires Java 25+ (Java is a software runtime that the Stirling-PDF server needs to operate) plus LibreOffice (a free office suite used for file format conversions) and Tesseract (the OCR engine) for full conversion support. That's more setup work, but the documentation covers it step by step.

First-run setup is minimal: the app works immediately after install. For team deployments you'll want to configure authentication and optionally connect external storage, but those are optional steps in the settings panel, not prerequisites.

Where it fits and what to compare it to

The straightforward comparison is Adobe Acrobat Pro, which runs about $24 per user per month on an annual plan. Stirling-PDF covers the most common Acrobat workflows: merge, split, sign, redact, convert, OCR, compress. The things Acrobat does that Stirling-PDF doesn't: deep annotation and review tools (comments, markups in the mature Acrobat style), and a highly polished desktop editing experience for complex PDF layouts. If your team's workflow is document processing rather than document authoring, Stirling-PDF is competitive. If you need rich inline annotation and commenting for design review or legal markup, Acrobat remains the more complete tool.

Other self-hosted PDF tools worth knowing:

• PDF4Teachers -- focused on document annotation and grading, not a general-purpose suite. Good for educators specifically.

• Docuseal (8,000+ stars) -- specialized in document signing workflows with a polished signer experience. If the primary need is "collect signatures on contracts," Docuseal is more purpose-built for that use case than Stirling-PDF.

• ILovePDF online tools -- the obvious cloud alternative. Free tier, no install, convenient. But your files go to their servers. For anything confidential, that's a policy question.

The honest comparison: most teams that currently use ILovePDF or Smallpdf for occasional PDF tasks can replace that workflow with Stirling-PDF. Teams that use Acrobat heavily for authoring and annotation should pilot Stirling-PDF for the processing tasks and keep Acrobat for the editing-heavy ones.

Verdict

Install it. For non-technical teams that handle sensitive documents, Stirling-PDF closes the gap between "we need professional PDF tools" and "we need to keep files off third-party servers." The free tier gives you the full tool set. The Docker install takes about ten minutes if you have Docker already. The desktop app is faster and requires nothing extra.

The caveats are real but manageable. The desktop app is single-user by design; team use needs the Docker deployment. The fat Docker image is large (several gigabytes) because it bundles LibreOffice and Tesseract for conversion tasks. And while the tool coverage is wide, Acrobat's commenting and annotation layer is more mature if your workflow involves collaborative document review.

None of those caveats disqualify it for the core use cases: contracts, compliance documents, HR paperwork, financial filings, anything your team regularly merges, signs, redacts, or converts. The project is actively maintained (88,000 stars, v2.14.2 released July 2026, 7,800+ forks), commercially backed, and documented well enough that a non-technical admin can manage the deployment.

If someone on your team is still emailing PDFs to a free online tool to merge them before an important meeting, Stirling-PDF is the fix.