Client Responsibilities
Clients MUST send all JSON API data in request documents with the header Content-Type: application/vnd.api+json without any media type parameters.
Clients that include the JSON API media type in their Accept header MUST specify the media type there at least once without any media type parameters.
Clients MUST ignore any parameters for the application/vnd.api+json media type received in the Content-Type header of response documents.
Server Responsibilities
Servers MUST send all JSON API data in response documents with the header Content-Type: application/vnd.api+json without any media type parameters.
Servers MUST respond with a 415 Unsupported Media Type status code if a request specifies the header Content-Type: application/vnd.api+json with any media type parameters.
Servers MUST respond with a 406 Not Acceptable status code if a request's Accept header contains the JSON API media type and all instances of that media type are modified with media type parameters.
Note: The content negotiation requirements exist to allow future versions of this specification to use media type parameters for extension negotiation and versioning.