The WP API opens a lot of custom client opportunities. Is there something you can add to the admin pages to help with syntax? The left side of that page is sparse. If the user enables REST and optionally a BASE, show some canned examples for the current type.
Better yet, add a page for custom post type API testing. Let the user select a post type that is REST enabled, ask them for filters like posts_per_page or orderby, and show the necessary syntax and a result of the query.
