REST (Representational state transfer) is a simple standard to exchange data among the http protocol. Most commonly it uses JSON (JavaScript Object Notation) as data format. However, XML, XHTML or CSV plain text are used as well. JSON is an interesting data exchange format for JavaScript based programs, because it brings the ability to convert JavaScript Objects directly back and forth to a data string. This makes it even possible to return code on demand, which means not only data is exchanged, whole objects including functions can be as well. REST is usually used by so called RESTful API's, which provide webservices to communicate REST.
sofision is very experienced in designing RESTful API's or implementing interfaces for various REST purposes.
A useful unofficial REST guide at at restfulapi.net
