How to force ASP.NET Web API to always return JSON?

Question

ASP.NET Web API does content negotiation by default - will return XML or JSON or other type based on the Accept header. I don't need / want this, is there a way (like an attribute or something) to tell Web API to always return JSON?

Answer 1

Clear all formatters and add Json formatter back.

GlobalConfiguration.Configuration.Formatters.Clear(); GlobalConfiguration.Configuration.Formatters.Add(new JsonMediaTypeFormatter()); 

EDIT

I added it to Global.asax inside Application_Start().

Answer 2

Supporting only JSON in ASP.NET Web API – THE RIGHT WAY

Replace IContentNegotiator with JsonContentNegotiator:

var jsonFormatter = new JsonMediaTypeFormatter(); //optional: set serializer settings here config.Services.Replace(typeof(IContentNegotiator), new JsonContentNegotiator(jsonFormatter)); 

JsonContentNegotiator implementation:

public class JsonContentNegotiator : IContentNegotiator {     private readonly JsonMediaTypeFormatter _jsonFormatter;      public JsonContentNegotiator(JsonMediaTypeFormatter formatter)      {         _jsonFormatter = formatter;         }      public ContentNegotiationResult Negotiate(             Type type,              HttpRequestMessage request,              IEnumerable<MediaTypeFormatter> formatters)     {         return new ContentNegotiationResult(             _jsonFormatter,              new MediaTypeHeaderValue("application/json"));     } }