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.
Vlasov Studio
Vlasov Studio helps Windows software developers write new code faster and understand existing code better. Their products solve critical programming problems and seamlessly integrate into Visual Studio.
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.