From http://www.w3schools.com (Copyright Refsnes Data)

Introduction to Web Services

Web Services can convert your applications into Web-applications.

Web Services are published, found, and used through the Web.

What You Should Already Know

Before you continue you should have a basic understanding of the following:

HTML
XML

If you want to study these subjects first, find the tutorials on our Home page.

What are Web Services?

Web services are application components
Web services communicate using open protocols
Web services are self-contained and self-describing
Web services can be discovered using UDDI
Web services can be used by other applications
XML is the basis for Web services

How Does it Work?

The basic Web services platform is XML + HTTP.

The HTTP protocol is the most used Internet protocol.

XML provides a language which can be used between different platforms and programming languages and still express complex messages and functions.

Web services platform elements:

SOAP (Simple Object Access Protocol)
UDDI (Universal Description, Discovery and Integration)
WSDL (Web Services Description Language)

We will explain these topics later in the tutorial.

The Future of Web services

Don't expect too much, too soon.

The Web Services platform is a simple, interoperable, messaging framework. It still misses many important features like security and routing. But, these features will be available as soon as SOAP becomes more advanced.

Hopefully, Web services can make it much easier for applications to communicate.