" GroupDocs.Viewer
HTML5 document viewer for your web, mobile & desktop apps.
Support for 50+ file formats, including PDF & Microsoft Office
On-premises & SaaS deployment options
User access control & SSL encryption
Works across all popular platforms
.NET Library Java Library Cloud API Cloud App
GroupDocs.Annotation
Add document annotation capability to your application or website.
Support for over 50 common document and image file formats
Several users can annotate the same document in real time
Support for native PDF & Microsoft Word annotations
14+ markup and commenting tools"