Top 5 Free & Open-Source PDF Libraries for Developers

Top 5 Free & Open-Source PDF Libraries

The Portable Document Format (PDF) is one of the most widely used file formats for sharing documents because it maintains consistent formatting across devices and operating systems. Whether you're building a web application, desktop software, or an automated document workflow, chances are you will need to work with PDF files.

Fortunately, there are numerous free and open-source PDF libraries that developers can use to create, read, and edit PDF documents without expensive commercial software. In this article, we’ll explore the top 5 PDF libraries available in 2025, highlighting their key features, use cases, and links to official resources.

1. iText

iText is one of the most widely recognized open-source libraries for PDF generation and manipulation in both Java and .NET. With its AGPL license, iText is ideal for open-source projects but also offers commercial licensing options for enterprise use.

Key features of iText include:

• Creating PDFs from scratch or from templates.
• Adding watermarks, annotations, and digital signatures.
• PDF encryption and password protection.
• Form filling and extraction of form data.

Official website: https://itextpdf.com/

2. Apache PDFBox

Apache PDFBox is a robust, open-source Java library developed by the Apache Software Foundation. It allows developers to create new PDF files, modify existing documents, and extract content such as text and images.

Notable features:

• PDF content extraction (text and images).
• Document splitting and merging.
• Command-line tools for quick PDF manipulation without coding.
• Supports PDF/A (archival) documents.

Official website: https://pdfbox.apache.org/

3. PDF.js

PDF.js, developed by Mozilla, is a JavaScript-based PDF renderer that runs in the browser. It’s commonly used to display PDFs in web applications, but it can also parse and extract data from PDF files.

Why developers love PDF.js:

• Pure JavaScript implementation—no server-side dependencies.
• Seamless integration with web apps and frameworks like React or Vue.
• Excellent performance for rendering PDFs in modern browsers.

Official website: https://mozilla.github.io/pdf.js/

4. PyPDF2

PyPDF2 is a popular Python library for PDF convertation. While it doesn’t support PDF creation from scratch, it excels at modifying existing documents.

Key features:

• Merge and split PDF files programmatically.
• Rotate and crop PDF pages.
• Add watermarks or annotations.
• Extract text and metadata from PDFs.

Python package repository: https://pypi.org/project/PyPDF2/

5. PDFSharp

PDFSharp is a free .NET library designed for on-the-fly PDF generation. It integrates seamlessly with C# applications, making it a preferred choice for .NET developers.

Highlighted features:

• Create new PDFs or modify existing ones.
• Draw shapes, text, and images directly onto PDF pages.
• Supports both GDI+ and WPF graphics APIs.

Official website: http://www.pdfsharp.net/

Conclusion: Choosing the Right PDF Library

Whether you're developing in Java, .NET, Python, or JavaScript, these open-source PDF libraries—iText, Apache PDFBox, PDF.js, PyPDF2, and PDFSharp—provide powerful and cost-effective solutions for PDF creation and editing.

When selecting a library, consider:

• The programming language and platform you’re working with.
• Specific needs such as encryption, form handling, or rendering.
• License compatibility for your project (AGPL, Apache, MIT, etc.).

By leveraging these tools, developers can streamline document processing workflows without relying on expensive commercial software.