Most modern web services are RESTful web services.
REST (stands for Representational State Transfer) is an architectural style for building web services.
The transport for REST is always done over HTTP (unlike SOAP).
HTTP verbs (GET, POST, etc) are used to indicate the kind of operation being requested. The input and output of REST request is typically JSON texts.
REST web services are generally simple and easy to construct. If is often said that REST popularity came from developers having had enough of the complexity (and bloated nature) of SOAP.
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