The important parts of your business are in the backend, and should be accessible in json format.
In my experience the backend of most non-tech and some tech businesses is a database and some trivial validation rules. Everything important is in the design of how the data is displayed on the front end.
IME a lot of data display is backend, that's why data gets joined, aggregated, enriched, etc. The front end just formats the data, into a table, list or whatever the onscreen representation is.
