Hey,

In this blog post, I want to show you how to configure ASP.NET WebAPI to send data as JSON

ASP.NET WebAPI is normally sending data as XML. The standard data-format in Javascript frameworks like Knockout.js or Angular.js is normally JSON. So to get ASP.NET WebAPI using only JSON can be configured in the Register-Method in WebApiConfig.

Here in the first part you can see clearing all formatters first and then add the JsonMediaTypeFormatter as the only formatter WebApi knows for my application. This makes sure I am only using JSON-format.

config.Formatters.Clear();
config.Formatters.Add(new JsonMediaTypeFormatter());

If you now sending requests to the API it should return the data as json.

var config = new HttpConfiguration();

config.Formatters.Clear();
config.Formatters.Add(new JsonMediaTypeFormatter());

config.MapHttpAttributeRoutes();

config.Routes.MapHttpRoute(
    name: "DefaultApi",
    routeTemplate: "api/{controller}/{id}",
    defaults: new { id = RouteParameter.Optional }
);

app.UseWebApi(config);

Consider that if a client is sending the Accept-Header in the request with a value your API does not support it will get no data. Although JSON is the de facto standard for REST-APIs you should always remember to have your API as easy and intuitive as possible to consume for your clients. So maybe if your API goes public think about having XML and JSON as formatters.

HTH

Fabian