Thanks for taking interest in GroupDocs.Viewer for .NET.
GroupDocs.Viewer for .NET is a standalone, back-end document rendering API that renders the source document’s pages into HTML pages or images as per user’s choice. When using the API in a web application, for instance, the rendering will be done on the server side and the user will view the HTML/image representation of the document in the browser. Hence, the documents will not be saved on client’s machine. Following are some useful resources that include documentation, example projects, and the open source document viewer applications that may help you understand the working of the API.
Furthermore, GroupDocs.Viewer for .NET also supports working with file streams. In your case, you can convert the byte array into file stream and then use that stream to render the document into HTML pages or images. For more details, please visit Working with Streams
In case you would have any questions or queries, please feel free to let us know.