When the documentation methods above are not sufficient, NiFi provides the ability to expose more advanced documentation to the user via the "Usage" documentation. When a user right-clicks on a Processor, NiFi provides a "Usage" menu item in the context menu. Additionally, the UI exposes a "Help" link in the top-right corner, from which the same Usage information can be found.

The advanced documentation of a Processor is provided as an HTML file named additionalDetails.html. This file should exist within a directory whose name is the fully-qualified name of the Processor, and this directory's parent should be named docs and exist in the root of the Processor's jar. This file will be linked from a generated HTML file that will contain all the Capability, Keyword, PropertyDescription and Relationship information, so it will not be necessary to duplicate that. This is a place to provide a rich explanation of what this Processor is doing, what kind of data it expects and produces, and what FlowFile attributes it expects and produces. Because this documentation is in an HTML format, you may include images and tables to best describe this component. The same methods can be used to provide advanced documentation for Processors, ControllerServices and ReportingTasks.