With inspiration/help from this article: https://skrift.io/issues/working-with-content-types-and-data-types-programmatically I have managed to create a new DataType that shows up at the right place 👍 code example: var dType = new DataType(editor, jsonSerializer, dataTypeSiteContainer.Id) { Name = name, DatabaseType = databaseType, }; await dataTypeService.CreateAsync(dType, UserKey); As you can i in the article, that shows how to do it in an earlier umbraco versjon, it is a Configuration that is added to DataType object. But this is not an available option in v15. I guess the replacement is either to use ConfigurationData or ConfigurationObject, and I have tried to figure out how to add block elements with those - not yet succeeded. Any docs, examples or tips that might help me on the way? 🙂 Thanx for helping out!