What Are Core Resources?
Expert API core resources are very common platform objects such as pages, files, users, and groups. These core resources appear in request and response HTTP messages across many different API endpoints. Consistent XML and JSON data representations of these resources allow for API integrations to contain reusable code to handle this data.
Not every possible API resource is considered a core resource. Some API endpoints accept and return resource data that are not common across the broader API endpoint collection.