Google maps is an example of an API.

Image courtesy of Google

How APIs Work

A conferencing API -- or any API for that matter -- allows a software application to communicate with a remote application over the Internet through a series of calls [source: TConsult, Inc.] An API is, by definition, an interface, something that defines the way in which two entities communicate [source: Thom Robbins.net Weblog].

With APIs, the calls back and forth between applications are managed through something called Web services. Web services are a collection of technological standards and protocols, including XML (Extensible Markup Language), the programming language by which applications communicate over the Internet.

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The API itself is a chunk of software code written as a series of XML messages. Each XML message corresponds to a different function of the remote service. For example, in a conferencing API, there are XML messages that correspond with each element required to schedule a new Web conference. Those elements include the conference time, the organizer's name and contact information, who's invited to the conference, the duration of the conference, et cetera.

Exactly how does a software developer leverage a conferencing API? He programs new or existing software to generate the right XML messages to tap the power of remote applications. Let's take conference scheduling, for example. With the right code, he could build conference-scheduling functionality into the company's existing e-mail system. Or, perhaps he could develop an entirely new instant messaging application that has one-click instant audio conferences.

Companies who release their API often do so as part of a larger software development kit (SDK) that includes the API, programming tools and other instructional documents to make the developer's job easier.

APIs and Web services are completely invisible to Web site surfers and software users. Their job is to run silently in the background, providing a way for applications to work with each other to get the user the information or functionality he needs.

Along with XML, the following technological standards, protocols and programming languages are what make Web services work:

  • SOAP (Simple Object Access Protocol): SOAP is responsible for encoding XML messages so that they can be received and understood by any operating system over any type of network protocol.
  • UDDI (Universal Description, Discovery and Integration): Described as a "yellow pages for the Internet," UDDI is an XML-based directory that allows businesses to list themselves, find each other and collaborate using Web services.
  • WSDL (Web Services Description Language): WDSL is the SOAP of the UDDI (enough acronyms for you?). Basically, WDSL is the XML-based language that businesses use to describe their services in the UDDI.

[source: Search SOA.com].

Now let's look at some examples of how software developers and businesses can leverage a conferencing API.