Sitecore custom client application

Question

I am trying to find information about a custom backend application in sitecore.
Can someone tell me how to create a new application in the sitecore backend, for example, "Content Editor", "Developer Center" or another in the working mode?

Answer 1

Here's a great article on building Sitecore Sheer UI applications:

My first user interface

Edit after @Martijn comment: you can add ASP.NET Webforms applications to the Sitecore desktop. Here are some links explaining how to do this:

Sitecore desktop app

External application inside Sitecore desktop