ComPDFKit
ComPDFKit enable developers to integrate PDF Annotations and Format Conversion, Digital Signature, Smart Forms, OCR, Redaction, and more in to their applications on Windows, macOS, iOS, Android, and the web through their PDF SDKs. Their aim is to offer the most comprehensive library to shorten the project development cycle and to continuously improve their SDK products to meet developer's future requirements as they change and projects evolve.
PDFlib
PDFlib GmbH is completely focused on PDF technology. Customers worldwide use PDFlib products since 1997. The company closely follows development and market trends, such as ISO standards for PDF. PDFlib GmbH products are distributed in more than 100 countries all over the world with major markets in North America, Europe, and Japan.
ActivePDF
ActivePDF provides a suite of easy to use, cost effective development tools for embedding feature-rich PDF functionality into server-based Windows applications. ActivePDF delivers robust, multithread, server-side PDF automation products which are intended for heavy-duty, enterprise-wide use. When you need it done now, need it done right, and need it every time, then ActivePDF provides the product, the support, and the level of confidence you need.