XML Web Services are modular, self-describing applications that can be published, located and invoked from anywhere on the web.

The beauty of web services is that neither the consumer nor the provider need worry about the operating system, language environment, or component model used to access them.

In fact, all you need to use a web service is an Internet connection and a browser.

What technologies are involved in Web Services?

XML, SOAP and HTTP are the base technologies of Web services architecture.

XML (Extensible Markup Language) is a W3C initiative that allows information and services to be encoded with meaningful structure and semantics that computers and humans can understand. XML is especially useful for information exchange and it is used by Web services to pass data and/or instructions back and forth between the provider and the consumer of the Web service.

SOAP (Simple Object Access Protocol) is a messaging protocol between computers e.g. the protocol that allows your computer to talk to the ePostcode server and vice-versa. It is a simple wire protocol that is based on XML and it allows remote computers to connect regardless of their operating system, programming language, or object model utilised.

HTTP (The Hypertext Transfer Protocol) is the set of rules for exchanging files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. Relative to the TCP/IP suite of protocols (which are the basis for information exchange on the Internet), HTTP is an application protocol. Because web services and SOAP use the HTTP protocol to exchange information ther are no problems passing through firewalls.

How can I use the ePostcode web service?

It's actually very simple. There are currently two separate web services for epostcode. 

The URL address of the current epostcode web services can be found at:

http://ws.epostcode.com/uk/postcodeservices09.asmx

This is the most upto date web service and contains all the functions and features required for supporting Google map functionality and the ePostcode client application.

The URL addresses of the deprecated ePostcode web services are:

http://ws.epostcode.com/uk/addressfinder.asmx

and

http://ws.epostcode.com/uk/postcodeservices.asmx

and if you click on the link you will be taken a page where you will find everything you need to consume the web service as well as a list of the methods available. The first web service has been superceded by postcodeservices.asmx, however the documentation on the site still relates to the first service addressfinder.asmx. We are in the process of updating our documentation and code samples to relate to the postcodeservices.asmx service that contains a more integrated and detailed set of Web Services.

From the link above you can get a formal definition or Web Service Description Language (WSDL) of the service by clicking on the Service Description link. This WSDL is all that developers need to enable them to integrate the service into a website, intranet or desktop application.

If you are interested in integrating ePostcode have a look at our Developer Centre where you will find code samples and downloads that should help you to get started. Have a go, it's a lot easier than you might think.

What functions does the ePostcode web service provide?

The ePostcode web service functions are listed below. For a more detailed description of these methods click on the corresponding link.

	Search Premise	The Search Premise functions allow you to search for Address Premises. An Address Premise is a Unique Delivery Point and a search will return a collection of 'List Address' and Unique_Identifiers for all the delivery points for the criteria in the search.
	Search Thoroughfare	The Search Thoroughfare functions allow you to search for Address Thoroughfares. An Address Thoroughfare is a Unique Street and Locality Location and a search will return a collection of 'List Address' and Unique_Identifiers for all the thoroughfares for the criteria in the search.
	Nearest Data	The Nearest functions return information about the distance between a datum postcode and a single reference postcode or list of reference postcodes.
	Geographics	The Geographic functions return geographics information for a postcode or list of postcodes.
	Get Address	The GetPremiseAddress functions return the full Postal Address of a Premise based on the Unique Delivery Point ID.