Request headers provide additional information for the request and the response of your API. Think of them like metadata for the operation. They can be used to augment other data for the response that does not belong in the body itself such as the content encoding. They can also be utilized by the client to provide information that can help the server process the response. Where possible we should always use the standard headers as this gives consistency to your user and provides them with a common standard across multiple endpoints from many different vendors.