WCF

Windows Communication Foundation (WCF) is a Microsoft framework for building and hosting service-oriented applications. It provides a unified programming model for creating distributed services that can communicate over various transport protocols and encodings, with an emphasis on interoperability, security, reliability, and transaction support. WCF services typically exchange messages using SOAP, but the framework also supports other formats and bindings that enable flexible integration with different platforms.

Core concepts in WCF revolve around contracts, endpoints, and hosting. A service exposes one or more service contracts that define operations a client can call. Data exchanged with these operations is described by data contracts. An endpoint combines an address, a binding (which specifies transport and encoding), and a contract, enabling clients to connect to the service. WCF supports multiple bindings such as basicHttpBinding for SOAP over HTTP, wsHttpBinding for WS-* features, netTcpBinding for high-performance TCP communication, and netNamedPipeBinding for on-machine communication. Security, reliability, and transactions can be configured at the binding and behavior levels.

Hosting options include integration with Internet Information Services (IIS) and Windows Process Activation Service (WAS) for managed hosting, or self-hosting within a custom application using ServiceHost. Clients generate proxies to call service operations, commonly with tools like svcutil. WCF provides built-in features for security (various authentication modes and message or transport security), reliable messaging, and distributed transactions, making it suitable for enterprise environments that require interoperable, long-running services.

In modern development, WCF’s server-side support on cross-platform runtimes has limited availability, with client stacks available in some environments and ongoing community efforts to port server functionality. For new cross-platform services, developers often consider RESTful APIs or gRPC as alternative technologies.