What is Web services in simple terms

Question

I am little bit confused about what really a web service is. You say Amazone web services,etc like that, they offer information. So what is the requirement to be a web url to be

Answer 1

What is a web service

It is many things. In programming, in generally refers to a web page, that can be called from an application (be it another web page, or desktop app), and the caller will pass in data to it, or receive data from it.

In this sense, it's basically like a 'method' or 'function' in a normal programming language; except you're calling it over the internet.

SOAP

A message format. As discussed above, a web service is a basically a 'method' or 'function'. SOAP is the 'instructions' and 'data' to this method. It will outline data types, and possibly a bunch of data as well. It is an XML format.

REST

REST is the means of implementing an interface to your application but, implementing access control, and other such things, specifically with HTTP Response codes. So you will get a 401: Denied (I think that's the right code), if you don't have access. There are other types of response codes that are useful. It also makes use of other HTTP commands like PUT/HEAD/OPTIONS.