Creating a JSON REST Webservice with WCF in .Net 4

First, create a normal WCF Service, with service contracts, datacontracts etc.

To make it JSON / REST, follow these steps:

Modify the Web.Config:
Application_Start:
RouteTable.Routes.Add(new ServiceRoute("test", new WebServiceHostFactory(), typeof(MyService)));
(Add System.ServiceModel.Activation.dll as reference)
 
This will make the webservice available at the following URL:
http://mysite/test
 
Add this on the service implementation class:
[AspNetCompatibilityRequirements(RequirementsMode=AspNetCompatibilityRequirementsMode.Allowed)]
 
This puts the webservice in ASP.Net compatibility mode.
 
Add this attribute above methods that should be available using GET:
[WebGet(ResponseFormat = WebMessageFormat.Json)]
 
There's lots of outdated info online (.Net 3.5 and older).
This is a nice tutorial for JSON, WCF and .Net 4
http://christopherdeweese.com/blog2/post/drop-the-soap-wcf-rest-and-pretty-uris-in-net-4