ServiceStack is an alternative to WCF and ASP.NET Web API that focuses on simplicity and speed. It uses a code-first approach with POCOs and strong typing. ServiceStack can automatically configure formats like XML, JSON, HTML, CSV and JSV. It includes endpoints for REST, RPC and SOAP and utilizes components like serializers, Razor plugins, an IoC container, logging/profiling and an ORM. ServiceStack is built on top of ASP.NET IHttpHandlers and uses simple POCO-based providers for caching, sessions and authentication that support multiple backends. It implements Martin Fowler's DTO pattern and allows rendering views using Razor for client applications.