The latest feature, introduced Tuesday, means purchases will be possible from within an app. This translates into more billing models, such as trying an app before buying, selling of virtual goods used in games, and selling upgrades.
Google listed several apps already using the service, including Comics by ComiXology, and several games, such as Tap Tap Revenge by Tapulous, Deer Hunter Challenge HD by Glu Mobile, and Dungeon Defenders: FW Deluxe by Trendy Entertainment.
Google has added documentation and a sample app in the Android software development kit to help developers incorporate the service. Security guidelines are also included.
"It's absolutely essential that you review the security guidelines to make sure your billing implementation is secure," Google said in its Android developers blog.
Google has set up the service so the Android Market handles all checkout details, so the application never has to directly process any financial transactions. The market uses the same checkout service employed during app purchases, which keeps the user experience consistent, says Google, creator of the Android operating system used in smartphones and tablets.
The transaction fee is the same for in-app purchases as for application buying. Google keeps 30% of the sale price and the developer gets the rest.
Apple has offered in-app purchasing on the App Store since October 2009. The feature not only gives developers more options for making money, it also can help combat piracy and reduce the number of apps in online stores by making it possible to combine free and paid services in one application, as opposed to having to provide separate free and paid apps.
In addition, Apple has suggested that in-app purchasing reduces piracy by providing a robust verification and authentication system. Pinch Media, a mobile advertising and analytics company, says at least 60% of paid apps using its analytics service have been pirated.
The Android Market has lagged the App Store in ease of use, a problem Google has been addressing. In February, the company launched an upgrade of the store that made it accessible from any desktop Web browser and also provided a less cumbersome way to search for applications.
Google also has had problems with security in the market. In March, the company confirmed that it had removed an undisclosed number of Android apps believed to be malicious applications. Mobile security firm Lookout identified at the time more than 50 apps infected with malware.
To avoid these problems and have more control over the buying experience, other companies have launched their own Android app stores. Amazon launched last week the Appstore for Android, leading to speculation that the company may be working on an Android version of the Kindle electronic reader.