Build Software Better and Faster with ComPDF Kit

Developers are using ComPDF Kit to boost their efficiency and create excellent products and services. With ComPDF Kit, you can integrate various PDF features across all platforms. Check the demo and contact sales today for more information.


Custom Solutions Designed to Meet Your Business Demands

ComPDF Kit is part of KDAN document services. Explore the capabilities of PDF viewer, annotations, editor, converter, and other PDF functionalities in ComPDF SDK.

Windows PDF Library

With C#, C/C++, Python, Java, ASP.NET, ASP.NET Core, VB.NET libraries, ComPDF Kit allows you to easily and quickly integrate PDF functionality like viewing, annotating, form filling, signing, and document editing into your Windows applications.

Web PDF Library

With JavaScript, TypeScript and C/C++ libraries, ComPDF Kit allows you to easily and quickly integrate PDF functionality like viewing, annotating, form filling, signing, and document editing into your Web applications. Support for all browsers (Chrome, Edge, Firefox, Safari, etc.) and major web frameworks (Electron, Vue, Nuxt, React, Next, Svelte, Angular, ionic angular, etc.).

Android PDF Library

With Kotlin, Java, and C/C++ libraries, ComPDF Kit allows you to easily and quickly integrate PDF functionality like viewing, annotating, form filling, signing, and document editing into your Android applications.

iOS PDF Library

With Objective-C, Swift, and C++ libraries, ComPDF Kit allows you to easily and quickly integrate PDF functionality like viewing, annotating, form filling, signing, and document editing into your iOS applications.

Mac PDF Library

By leveraging Objective-C, Swift, and C++ libraries, ComPDF Kit empowers you to seamlessly and efficiently incorporate advanced PDF features into your Mac applications. This encompasses tasks such as viewing, annotating, form filling, signing, and editing documents.

Server PDF SDK Library

Deliver dependable solutions for server platforms, including Java, .NET Core, Python, PHP, C/C++, Processor, and command-line tools, facilitating the seamless processing of PDF files. Multi-threaded and distributed environments are supported. Realize essential PDF functions, such as generation, viewing, editing, document comparison, OCR, conversion, and more, within server applications.

Flutter PDF SDK

Use the professional Flutter library to integrate PDF functionality into your iOS and Android apps, enjoy Flutter's flexible development experience, high performance, and beautiful interface, and realize PDF preview, editing, signing, cipher marking, annotating, and other functions.

React Native PDF SDK

Incorporate our professional cross-platform PDF SDK solution. Empower your users to view, edit, annotate, convert formats, redact, merge, split, fill out, and encrypt PDF files.


Professional HTTP API allows you to easily and quickly integrate PDF functionality into applications across all development platforms without worrying about the compatibility of programming languages with the API. Supports remote invocation and private deployment.

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Integrate PDF Functionality on All Platforms

Discover the full potential of ComPDF Kit across various platforms, including Web, Windows, Android, iOS, Mac, and Server, as well as cross-platform frameworks like React Native, Flutter, and more!



ComPDF Kit presents a robust reading engine, ensuring stable and swift opening, even for large files. It encompasses theme modes, navigation, search, magnification, page-turning effects, bookmarks, outlines, and more.



Empower your application to add and edit annotations, including markups, shapes, free text, notes, ink, stamps, links, sound recordings, and more. ComPDF Kit is fully compliant with PDF specifications and is compatible with other PDF software.


Edit PDF Content

The PDF editing SDK addresses the demands of PDF editing, providing robust support for adding, deleting, editing, and moving PDF texts, images, and pages.


Fill Forms

Create fillable forms for receipts, contracts, and tax documents effortlessly with ComPDF Kit. The SDK offers a variety of tools, including text fields, drop-down lists, table borders, checkboxes, buttons, and signatures.



Incorporating with the signing SDK, users can insert signatures or collect signatures from others. The SDK supports electronic and digital signatures, meeting diverse signing requirements.


PDF Security

The KDAN PDF SKD provides standard encryption with RC4 and advanced algorithms AES-128 & AES-256 to cater to the diverse security needs of your projects. The SDK delivers encryption, decryption, permission settings, Bates numbering, headers and footers, and more.



Effortlessly overlay and irrevocably remove sensitive or confidential text or images from PDF documents. Support the customization of style, color, and explanatory text for redactions.

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Seamless Integration with ComPDF Kit

ComPDF Kit is easy to integrate with a few lines of code.

Viewing a PDF
Creating an annotation
using ComPDFKit.PDFDocument; using ComPDFKit.PDFPage; using ComPDFKit.PDFAnnotation; // Load a document. CPDFDocument document = CPDFDocument.InitWithFilePath("Test.pdf"); // Get the first page. CPDFPage page = document.PageAtIndex(0); // Create a freetext annotation in the page. CPDFFreeTextAnnotation freeText = page.CreateAnnot(C_ANNOTATION_TYPE.C_ANNOTATION_FREETEXT) as CPDFFreeTextAnnotation; // Set the textual content associated with the annotation. string str = "Hello world"; freeText.SetContent(str); // Set the bounding box for the annotation in page space. freeText.SetRect(new CRect(0, 100, 160, 0)); // Set text attribute. CTextAttribute textAttribute = new CTextAttribute(); textAttribute.FontName = "Helvetica"; textAttribute.FontSize = 12; byte[] fontColor = { 255, 0, 0 }; textAttribute.FontColor = fontColor; freeText.SetFreetextDa(textAttribute); // Set the horizontal alignment of text within the bounds of the annotation. freeText.SetFreetextAlignment(C_TEXT_ALIGNMENT.ALIGNMENT_CENTER); // Update appearance stream for the annotation. freeText.UpdateAp();

Powered by ComPDF Kit



ibon is designed for connecting ibon cloud printing service. With ComPDF Kit integration, the ibon app enables users to preview files before they upload files to ibon cloud. Then they can go to any 7-11 store to print the documents without spending time checking files when using the actual machine.


Taiwan Intellectual Property Office (TIPO)

Taiwan Intellectual Property Office (TIPO) is an administrative agency responsible for IP policy formulation, IP laws drafting, and inter-agency enforcement coordination. TIPO integrates KDAN's PDF SDK with their intranet document system where the employees can review and edit PDF documents for patent applications, including invention, utility model, and design patents.



DottedSign is a cloud-based e-sign service. Integrated with ComPDF Kit, its iOS and Android apps allow users to facilitate PDF viewing and editing functionalities. Users can add signatures, text and stamps onto PDF documents right from their smart devices.

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