Amazon has announced an extension of its in-app purchasing API, already available for the Kindle Fire and other Android devices, for games on Windows PCs, Macs and the web. The move is aimed at expanding the reach of its e-commerce platform and essentially means game developers will be able to support micro transactions for virtual goods and currencies on those platforms using Amazon as an intermediary.

The company will take a 30% cut of revenue from each purchase, which is the same amount it takes from full app sales and the same rate that Google and Apple charge for purchases on their platforms.

But the online retailer believes it can offer some advantages over its rivals. For one thing, they already have a  customer base of around 30 million people with their credit cards on file and ready to purchase. On an FAQ page for game developers, Amazon cites an independent study that "found that Amazon's In-App Purchasing generates almost 4x the revenue per user as compared to Google Play" on Android devices.

Regular credit cards, as well as Amazon's own "virtual currencies" such as Amazon gift cards and other Amazon credits tied to an account will be accepted to make in-game purchases on the new platforms.

The company also says in-app items will be available on automatically, increasing their visibility by showing up on things like best seller lists and recommendations on related products.

"We're passionate about making game developers successful, and we'll continue to build services that make monetization easier and remove undifferentiated heavy lifting from developers," Amazon Games Director Mike Frazzini said in a press statement. The company goes on to point out the extension of in-app purchasing is just one part of a larger family of end-to-end services for developers, including Amazon Web Services for hosting and storage, to Amazon Dynamo for database storage, and Game Circle software to incorporate leaderboards, achievement rankings and other lists into games.