Web Service Application Programming Interface (API) is an interface implemented by a software program to enable interaction with other software, similar to the way a user interface facilitates interaction between humans and computers.

The API (Application Programming Interface) has been an essential component for creating applications that hook into or utilize web apps such as Facebook and Flickr. The practice of publishing APIs has allowed web communities to create an open architecture for sharing content and data between communities and applications.

In this way, content that is created in one place can be dynamically posted or updated in multiple locations on the web. Sharing live comments made on Twitter to a Facebook account, for example, is enabled by Twitter and Facebook’s APIs. With it, developers have been able to create some amazing mashups and tools. Some of the most helpful applications on the web wouldn’t be possible without APIs. Here are my pick of the best 10 on the web…

1. Google Maps API

The Google Maps API is the most used code on the web. It lets you embed Google Maps in your own web pages with JavaScript. The API provides a number of utilities for manipulating maps and adding content to the map through a variety of services, allowing you to create robust maps applications on your website. While most API’s are data servers, with the Google Maps API you take control of an instance of the application itself using JavaScript. To use a Google Maps you need an API key

2. Flickr API

Flickr is an image and video hosting website, web services suite, and online community. There are hundreds, if not thousands, of mashups that rely on the Flickr API to add a little bit of visual appeal. With 3-5 million new photos uploaded to the site daily and recently passing the 4 billionth photos, it’s no wonder that developers are excited to use it. It’s a simple call-and-response-based API, but with extensive tailored support for your chosen language. It communicates using REST, XML-RPC or Soap and gets your data back in XML, JSON or PHP. One of this API’s great strengths is the number of third-party developer tools and libraries. For more information on Flickr’s API visit the Official Flickr API documentation page, which offers a ton of information about using the API and links to third-party API kits.

3. Facebook Platform / Facebook Connect

Facebook is the king of the social media network. The site is driven by user contributions, offering coders a rare platform that hooks you directly into an eager audience. Facebook’s bespoke mark-up language – PHP and FBML are use for coding their Apps. With over 350,000 active applications on the Facebook Platform and Facebook Connect, that easily makes Facebook’s platform and Connect API among the hottest development platforms on the web today. More information on this can be found at the Facebook Developers site, one of the most complete and well-made and maintained developer sites on the web.

4. Twitter API

Twitter is a community with one question: “What are you doing now?” The API lets you take that data in XML format and combine it with your own code or other API’s predictably; geographic mapping applications top the list, showing the location of group members. The place to start, of course, is the Official API Wiki, which Twitter has packed with documentation, guides, tutorials, known issues, and FAQs for dealing with the Twitter API and OAuth

5. eBay API

eBay’s API is more powerful than ever, and offers plenty of functionality for creating powerful and interesting applications. Normally, users buy and sell items using the eBay online interface, interacting with eBay directly. But with the eBay API, you communicate directly with the eBay database. Of the services in our countdown, eBay’s API is the best-supported. It’s the most comprehensive and complex of the bunch. After registering, you’re able to generate a set of authentication keys for the API’s sandbox to build and test sample applications.

6. Amazon e-Commerce API

Amazon’s E-Commerce Service (ECS), an industrial-strength collection that Amazon describes as “The best way to make money on the internet”. ECS gives you back-end access to Amazon, enabling you to build seamless store fronts into your own website using the “most modern computer language”. The API provides programmatic access to Amazon’s product selection and discovery functionality so that developers can advertise Amazon products to monetize their website. As you might expect, Amazon’s is a security conscious provider, so you will need to create a dedicated web services account at (aws.amazon.com) where you will be assigned a unique access key.

7. YouTube

YouTube APIs and Tools enable you to integrate YouTube’s video content and functionality into your website, software application, or device. The video site’s API offers only a handful of functions, which return XML data in response to REST or XML-RPC calls.

• The Data API lets you incorporate YouTube functionality into your own application or website. It returns data in fixed sets that allows you to perform searches, upload videos, create playlists, and more.
• YouTube Direct allows you to request user generated content from your site visitors, moderate the submissions, and display them on your site.
• The Custom Player takes you a step beyond just pasting a video into your site. You configure the custom player to show playlists, favourites, or their own videos.
• The Player APIs give you control over YouTube video playback on your website.
• Widgets are simple page elements you can embed in your website to give it YouTube functionality. It allows users to perform a video search just by adding some JavaScript to your page.
• The Developer Dashboard shows you at a glance the number of API requests, playbacks, uploads and errors that your app is generating.

You’ll need to sign up for a developer account to use the YouTube API.

8. Digg API

Digg is a social news website and offers a comprehensive, complex API that responds to HTTP GET or POST queries by returning data in a specified format. The API offers XML, JSON data formats and scripting with JavaScript or PHP. The Digg API documentation details dozens of end points or data locations and you can access individual stories, comments or data on particular user activities.

9. Delicious API

Delicious, the world’s leading social bookmarking service combines search and tag features to make your favourite sites easier to find. The API is a straight forward REST-based handful of functions. Though it’s not well documented as many other APIs, Delicious is so simple you can see result just by typing a URL into your browser, using your Delicious log-in.

10. FeedBurner API

Rss feed creation tool FeedBurner offers developers an established library of APIs for interacting with the service. FeedBurner is a web feed management provider that provides custom RSS feeds and management tools to bloggers, podcasters, and other web-based content publishers. youtube playlist