What is WCF?

Windows Communication Foundation, sometimes shortened to just WCF, previously codenamed Indigo, is a new communication subsystem to enable applications, in one machine or across multiple machines connected by a network, to communicate. WCF applications can be developed in any language which can target the .NET runtime.

The WCF programming model unifies Web Services, .NET Remoting, Distributed Transactions, and Message Queues into a single Service-oriented programming model for distributed computing. It is intended to provide the rapid application development methodology to the development of web services, with a single API for inter-process communication in a local machine, LAN, or over the Internet. WCF runs in a sandbox and provides the enhanced security model all .NET applications provide.

WCF uses SOAP messages for communication between two processes, thereby making WCF-based applications interoperable with any other process that communicates via SOAP messages. When a WCF process communicates with a non–WCF process, XML-based encoding is used for the SOAP messages but when it communicates with another WCF process, the SOAP messages are encoded in an optimized binary format. Both encodings conform to the data structure of the SOAP format, called Infoset.