The RightsLine API is organized around REST, built using ServiceStack. Our API is designed to have predictable, resource-oriented URLs and to use HTTP response codes to indicate API errors. We use built-in HTTP features, like HTTP authentication and HTTP verbs, which can be understood by off-the-shelf HTTP clients. JSON or XML will be returned in all responses from the API, including errors (though if youโ€™re using API bindings, we will convert the response to the appropriate language-specific object).