Use custom fields to extend a resource scheme to include custom data that is not provided as a common field. Depending on the resource on which the custom field is added, it may be available in the Rebilly UI.
Example: A custom field called preferredCommunicationChannel is added to the customer resource. It has two allowed values, which are 'email' and 'phone'.
{ "customFields": { "preferredCommunicationChannel": "email" } }
For detailed information on Rebilly resources, see Resources.