Stirling PDF: 50+ free PDF tools you can run yourself
Stirling PDF puts 50+ PDF tools - merge, split, sign, redact, convert, OCR, compress and more - in one free, open-source package. Run it as a desktop app or on your own server, and your files are processed on your machine instead of being uploaded to outside websites.
Official publisher artwork hosted by its publisher. Official source. Independent guide, not affiliated or sponsored. Artwork and trademarks belong to their owners.
Image: official Stirling PDF interface screenshot, from the project's website.
Quick facts
- What it is: a free, open-source PDF platform with 50+ tools - the project's core code is under the MIT licence, while some directories of the repo (proprietary, SaaS and desktop-specific parts) carry separate licences. The project describes three ways to run it: a personal desktop app, in the browser, or self-hosted on your own server with a private API.
- Privacy: when you run it locally (desktop app or your own server), your documents are processed on that machine and not sent to external services. That local-processing promise applies to your own deployment - a copy hosted by someone else is only as private as their setup.
- Price: the project is free and open source; we did not find per-file fees or watermarks advertised for the self-hosted version. Some repo components sit under separate licences, and the team also offers hosted/enterprise options.
- Extras: no-code automation pipelines in the UI plus an API, so repetitive jobs (for example compressing hundreds of files) can be automated.
- Best for: anyone handling certificates, applications, bank statements or office documents who does not want to upload them to random "free PDF" websites.
What it is
Most free PDF websites make you upload your document to their server - fine for a menu, not fine for an Aadhaar form, salary slip or contract. Stirling PDF flips that when you run it yourself: the tools execute on your machine or your own server, and files are processed locally. It covers the everyday jobs (merge, split, compress, rotate, convert to/from Word and images), the office jobs (sign, redact, watermark, add page numbers), and the heavy jobs (OCR scanned documents, automate multi-step workflows). The GitHub project describes itself as the "#1 PDF Application on GitHub" and the official website reports 30M+ downloads - both are the project's own claims.
Image: official Stirling PDF automation pipelines view, from the project's website.
Is it free?
Yes for the self-hosted core - the project's licence file puts most of the code under MIT, with proprietary, SaaS and desktop-specific directories under their own licences. Self-hosting with Docker is one command (the docs show a single docker run), and the project also describes a desktop client. The team sells hosted/enterprise options around it, so check the current terms if you need those parts.
India
- When you run it yourself, processing happens on your own machine without depending on an outside PDF service - useful for sensitive documents.
- A strong default recommendation for students filling scholarship and admission PDFs, and for small offices digitising records.
Good to know
- Docker route: one command from the README starts it on port 8080; desktop route: download the app from the official site or GitHub releases only.
- Self-hosting for family or office use means you handle updates and access control - keep it on your local network unless you know how to secure it.
- OCR quality depends on scan quality; very old or faint documents may still need manual checking.
Frequently asked questions
Is Stirling PDF free?
The self-hosted core is free and open source (MIT licence for most of the code; some directories under separate licences).
Do my files get uploaded anywhere?
Not when you run it yourself - local deployment is its main promise: processing happens on your own machine or server. A Stirling copy hosted by someone else follows their setup, not this promise.
Can it do OCR on scanned Malayalam/English documents?
It includes OCR tooling for scanned PDFs; results depend on scan quality and the OCR language data you install.
Sources: Stirling PDF on GitHub, Stirling PDF, Docs. Checked 22 October 2026.