Soap-Ui is used to automate Web services.Web services is also known as API

If we click news link on google , news provided on google are gathered from other websites like bbc , nytimes ,fox news etc.

Another example is expedia.com which gathers info from all the air line websites to give us a list of available options if we want to fly from one destination to another in a given time frame.

Soap and Rest are the protocols which set up the guidelines to be used when data is to be exchanged between two applications using web services. These days people are moving towards rest.

WSDL-WSDL is a document which is used to define what all goes as information between 2 websites when using Soap protocol.The request and response protocols are defined by WSDL. WSDL for the web service to be tested is given by developer to the tester

Rest does not use any WSDL. Rest Protocol is completely different.Request and responses follow a set of protocols.

Soap-Ui testing is both manual and automate testing for web services.

Soap-UI can test both soap and rest protocols.

Soap-UI can parameterize test cases from excel files as well. Language used by Soap-UI is groovy.

Groovy language is based on Java.