In RSS Ground we work with content feeds from various content providers, as well as generate our own feeds. We work with RSS and Atom and some other feed formats. Any feed has to be valid in order to be used in RSS Ground. And you can use online validation services to figure out if your feed is valid.
All feeds generated in RSS Ground are valid RSS feeds and are guaranteed to work well inside the service. We also use Atom format to generate your custom feeds. Since custom feeds consist of content from various external feeds, it is hard to guarantee they will be valid. However, we do our best to make sure custom feeds will work fine with our tools, as well as in any other third-party services.
Read more about custom feeds