Why doesn't REST utilize WSDLs, unlike SOAP?

rest, soap, web-services, wsdl

Solution

REST really only uses the HTTP verbs (`GET`, `PUT`, `POST`, `DELETE`, …) on a resource. All operations on a resource are supposed to be represented that way. `POST` is used as a catch all for when you can't express your business logic in a way that fits into the other three. That is why there isn't really a WSDL for a REST service since you only ever have 4 methods on the resource.

But you still have the possibility to describe a REST web service with WSDL 2.0.

Problem

For SOAP web services there is a specification which all request/responses must follow. This specification is in the form of a WSDL document. However for REST web services, why is there no such specification or WSDL? Does this make REST more vulnerable to runtime exceptions because we are not following any specifications?

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