A content type is a managed, reusable structure for creating and delivering content relating to a specific purpose. A content type can incorporate other content types, allowing modularity. For example, a speaker bio may be a simple content type, which can be included within other content types such as an event description or a listing of speakers. Some elements within a content type will be required, while other elements are optional. Through the use of optional elements, content types can support variants that change what elements are presented within content items.