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 you’re using API bindings, we will convert the response to the appropriate language-specific object).