Soap- SOAP has become the standard for exchanging XML-based messages. The basic structure of SOAP is like any other message format (including HTML itself). Rest-Representative State Transfer In RESTful web services, the emphasis is on simple point-to-point communication over HTTP using plain old XML (POX). REST is an architectural style that can be summed up as four verbs (GET, POST, PUT, and DELETE from HTTP 1.1) and the nouns, which are the resources available on the network (referenced in the URI). Rest - architecture, Soap - protocol. Soap - more standard, better support for error handling, but more heavie and difficult to understand. Rest -simpler to understand and develope. not usefull for ditributed systems, where message may go through one or more intermediaries. Lack of standards support for security, policy, reliable messaging, etc