StirlingPDF: Free Open-source PDF Tools & API

StirlingPDF: Free Open-source PDF Tools & API

PDF files are a staple of digital document management, and having the right tools to handle them efficiently is essential.

StirlingPDF is a robust, open-source solution that provides a comprehensive suite of PDF operations. Whether you need to organize, convert, secure, or edit your PDF files, StirlingPDF has you covered with its extensive features and API integrations.

In this article, we will explore the capabilities of StirlingPDF and how it can cater to all your PDF needs.

Watch our SirlingPDF platform overview


StirlingPDF offers a full interactive GUI for managing PDF pages, making it easy to split, merge, rotate, and reorder pages. You can merge multiple PDFs into a single file or split a PDF into multiple files at specified page numbers. The tool also allows for the extraction of individual pages and the reorganization of pages into different orders.

Features like rotating PDFs in 90-degree increments and removing unwanted pages ensure that you can tailor your documents to your exact specifications. Additionally, StirlingPDF supports multi-page layouts, scaling page content, adjusting contrast, cropping, and auto-splitting PDFs using scanned page dividers.


Conversion is one of the standout features of StirlingPDF. It supports converting PDFs to and from images, which is perfect for creating high-quality visual content. Using LibreOffice integration, you can convert common file types such as Word, PowerPoint, and HTML into PDF format. This makes StirlingPDF a versatile tool for creating PDFs from various sources.

Moreover, StirlingPDF supports markdown to PDF conversion and URL to PDF conversion, ensuring that you can easily turn web content and markdown documents into professional PDFs.


The StirlingPDF API is a powerful feature that allows for seamless integration with external scripts and applications. This API enables developers to automate PDF operations, making it ideal for workflows that require frequent PDF manipulations. The API supports all major functionalities, including file processing, conversion, and security features, ensuring that you can embed StirlingPDF’s capabilities directly into your applications.


StirlingPDF’s parallel file processing and download capabilities enhance efficiency and productivity. You can create pipelines to automate repetitive tasks, such as converting multiple documents or splitting large PDFs into smaller, more manageable files. This feature is particularly useful for organizations that handle large volumes of PDFs and need to streamline their processes.

Sign & Security

Security is a top priority when handling PDF documents. StirlingPDF provides robust security features, including the ability to add and remove passwords, set and change PDF permissions, and certify/sign PDFs. You can also add watermarks, sanitize documents to remove sensitive information, and auto-redact text.

For added convenience, StirlingPDF supports generating and adding signatures, ensuring that your documents can be securely signed and authenticated.

View & Edit

StirlingPDF includes comprehensive tools for viewing and editing PDFs. You can view multi-page PDFs with custom sorting and searching capabilities. The tool allows on-page editing features such as annotation, drawing, and adding text and images, using PDF.js with Joxit and Liberation fonts.

In addition to basic viewing and editing, StirlingPDF offers features like adjusting contrast, scaling page content, cropping, and flattening PDFs. You can also edit metadata, extract images, add page numbers, and auto-rename files by detecting PDF header text.


File size can be a concern when dealing with large PDFs. StirlingPDF includes powerful compression tools to reduce PDF file sizes without compromising quality. Using OCRMyPDF, the tool can compress PDFs, extract images, and even perform OCR (optical character recognition) to enhance text searchability.


StirlingPDF stands out as a comprehensive, open-source solution for managing PDF documents. With its extensive range of features, from organizing and converting PDFs to securing and editing them, StirlingPDF caters to all your PDF needs. Its API integration and parallel processing capabilities make it an ideal choice for developers and organizations looking to automate and streamline their PDF workflows.

Explore the power of StirlingPDF and elevate your PDF management to the next level.