APIs allow outside developers to connect with and build applications on top of web services like Facebook, Twitter and now Google+. In fact much of the success of Twitter and Facebook is a result of both services’ developer APIs. If Google+ is to have any hope of catching its competitors it needs a strong API.
Unfortunately what Google has unveiled so far isn’t much of an API. The current version of the Google+ API limits developers to read-only access of public posts. If you were hoping to see apps that tracked your circles or allowed you to post from a desktop app the new API will leave you wanting.
As it stands, the Google+ API is little more than an easier, officially-sanctioned way to screen scrape public Google+ posts.
Google is aware of the APIs shortcomings, calling it a “first step,” and plans to expand the Google+ API in the future. Presumably the first order of business will be adding write-access so that outside apps can interact with Google+ rather than simply consuming Google+ posts.
Of course if you’ve been trying to add Google+ support to your app without these APIs, you can throw away your HTML parsers and enjoy RESTful methods that return JSON to a properly authenticated app (the authentication is handled by OAuth 2). Google has also released a set of client libraries for Python, Ruby, PHP and other popular languages.
It’s limited at the moment, but if you’d like to get started now, so you know what’s going on when the full-featured version arrives, head on over to the Google+ Platform Blog which has a short tutorial and plenty of sample code to get you rolling.