ZetPDF is described as 'C# ASP.NET VB.NET PDF API to create PDF documents from scratch using API or XML. PDF library for Windows Forms, WPF and Silverlight as well' and is an app in the Office & Productivity category. There are more than 10 alternatives to ZetPDF for a variety of platforms, including Online / Web-based, Windows, Linux, Mac and Self-Hosted solutions. The best alternative is Document Cyborg, which is free. Other great apps like ZetPDF are PDFium (Free, Open Source), HTML to PDF Converter Library for .NET (Paid), Pdfcrowd (Paid) and PDFSwitch (Free Personal).
The Apache PDFBox™ library is an open source Java tool for working with PDF documents. This project allows creation of new PDF documents, manipulation of existing documents and the ability to extract content from documents.