We are pretty sure now almost everyone knows what a Google+ hangouts is. It is the one of the popular buzz word in the social media world and one of the most widely used Google+ feature to date.

Hangouts are used in many creative ways from individuals to media. We have wrote numerous posts about its usage right from CNN using hangouts, YouTube integration of hangouts to watch videos together and more. You can search on our site for hangouts to find more posts about hangouts. Yesterday we also wrote about some new cool features coming out as part of Google+ hangouts extras.

But all these new features were from Google+ team. Developers outside google were looking for a way to extend the functionalities of Google+ hangouts. Ideal would be an api (application programming interface), so that developers can start developing cool and innovative applications, integrate with other systems and so on.

That day has finally come, Google+ team has released a Google+ hangouts API in developer preview mode for developers to get started.

Here is a short description about the api according to google…

The Google+ Hangouts API allows you to develop collaborative apps that run inside of a Google+ Hangout. Hangout apps behave much like normal web apps, but with the addition of the rich, real-time functionality provided by the Hangouts APIs. Apps have the ability to control aspects of the user interface, synchronize data between hangout participants, and respond to various events in the hangout.

More details about the api is found at Google+ hangouts developer site.

Writing an app for Hangouts is pretty simple. Google+ team has taken the same standard approach similar to writing a chrome extension. All you need is XML, HTML, Javascript and CSS.

Basically you write the UI and functionality using html, javascript and css. Then you have to create a simple Gadget XML manifest file with details about the app and the xml must be hosted on a server that is publicly accessible by google servers. You could simply host it on GAE (Google App Engine).

More details about Writing a simple hangouts app along with sample found on the Google+ developers site.

Here are the steps to use an app in hangout

• First you have to register the Gadget XML file.
• For that simply goto Google API’s Console, enable the Google+ hangouts API services (Click on the ON button again Google+ hangouts API)
• Once enabled, you’ll find a new link in the API console called Hangouts, click on it
• In the following screen, It will ask for the Gadget XML URL, enter the full url of the gadget manifest xml you created and hosted on your server (for eg. http://hangoutsapi.appspot.com/ggs/yesnomaybe.xml)
• Click on the Save button
• Now a new Link will appear below called as Enter a hangout
• Click on the link to launch the hangout window
• Now click on the Hangout button
• Now the hangout will be loaded
• Look for a wheel icons with text saying Apps in the bottom left of the hangouts screen
• Click on that Apps icon
• Now your app will be loaded on the top of the hangout screen and you can start using it. You’ll also find Get My Apps, Reload app and Reset app state buttons on the top right to play with your app.