SOAP: Simple Object Access Protocol, is a protocol to communicate with a web service. SOAP is a xml which travels over http. SOAP xml can be a request or response.



WSDL: Web Servivce Discription Language, again this is a xml which describes about the web service. What kind of methods this webservice expose and wat are the parameters need to be passed for every method & what is the return value. If any of the method expects a complex type(non statndard java type) the WSDL contains the schema for the complex type.It contains information where this webservice is running.





Both the above are xml and are in a standard format given by w3c organization. As webservices maintain the same standard the webservices became language independent.