All response messages MUST support an application/hal+json (HAL) format.
The application/problem+json (Problem Detail) MUST be used to communicate details about an error.
Request messages with body SHOULD support an application/json (JSON) format. Where applicable, the request message SHOULD also support the application/hal+json format.
Request messages MAY also support the application/x-www-form-urlencoded (URL Encoded) format.