This is everything you need to register a servicestack service in Sitefinity. Just set your Route, and make sure to register the plugin in App_Start.

CodeRushServiceStackTemplate.cs

using System;
using System.Collections.Generic;
using System.Linq;
using Telerik.Sitefinity;
using Telerik.Sitefinity.Model;
using Telerik.Sitefinity.DynamicModules;
using Telerik.Sitefinity.Data.Linq.Dynamic;
using Telerik.Sitefinity.Services.Search;
using Telerik.Sitefinity.Utilities.TypeConverters;
using ServiceStack.Text;
using ServiceStack;
using Telerik.Sitefinity.DynamicModules.Model;

namespace «FieldStart»«TextLink("MyNamespace")»«FieldEnd» {
    #region PLUGIN
    public class «Link("Custom")»ServicePlugin : IPlugin
    {
        /// <summary>
        /// Call this at Global.asax, Application_Start
        /// SystemManager.RegisterServiceStackPlugin(new «TextLink("MyNamespace")».«Link("Custom")»ServicePlugin());
        /// </summary>
        public void Register(IAppHost appHost)
        {
            appHost.RegisterService(typeof(«Link("Custom")»Service));
        }
    }
    #endregion

    #region SERVICE
    public class «FieldStart»«Caret»«Link("Custom")»«BlockAnchor»«FieldEnd»Service : Service {
        public object Any(«FieldStart»«Link("MyFirstRequest")»«FieldEnd» request) {
            return "Hello World";
        }
    }
    #endregion

    #region REQUEST
    [Route("/«FieldStart»«TextLink("route")»«FieldEnd»")]
    public class «Link("MyFirstRequest")» : IReturn<string> {
        public string Param1 { get; set; }
    }
    #endregion
}