Web services are client and server operations that communicate over the World Wide Web (WWW) using the Hypertext Transfer Protocol (HTTP). They are self-contained, modular, distributed, dynamic applications that can be described, published, located, or invoked over the network to create products, processes and supply chains. They are built on top of open standards such as TCP/IP, HTTML, HTML, and XML.
There are two main types of webservices: SOAP and REST. SOAP (originally Simple Object Access Protocol) is a protocol specification for exchanging structured information in the implementation of web services in computer networks.
REST stands for REpresentational State Transfer. REST is a web standards-based architecture and uses HTTP Protocol for data communication.
In Kalipso you can use Web services to send and receive data. Kalipso supports both SOAP and RESTful Web Services.