Amazon is the world’s largest online retailer and it sells just about everything. It’s also host to one of the world’s largest mobile platforms with its Kindle Fire devices and Amazon Appstore for Android. Now the retailer is combining the two.

Amazon announced today the launch of the Mobile Associates API. It’s a new tool that allows developers to integrate Amazon’s retail store into their mobile apps. In other words, a developer could sell physical items via in-app purchases, and the sale of those physical items would be handled by Amazon’s retail operation.

“Developers now have the ability to create an even deeper connection between their app and the products customers value and purchase through Amazon.com,” said Mike George, Vice President of Amazon Appstore, Games and Cloud Drive. “Imagine a developer of a nutrition and fitness app can now offer their customers the ability to purchase vitamins, supplements and fitness gear within the app, directly from Amazon.com. It offers the customer a more relevant experience and provides the developer with a new source of revenue.”

It’s noted that the API can do more than just sell physical items in apps. It can also be used to bundle digital and physical purchases. Amazon uses the example of a person buying a board game and receiving the digital version of the same board game for free.

The API is also being used by mobile games that are tied into popular brands, like Marvel. Animoca, developer of Thor: Lord of Storms, integrated the API so that users could purchase Thor toys from within the app and earn in-app currency for doing so. This also nets the developer a sales commission from Amazon.

In short, the Mobile Associates API is a pretty big deal. Amazon is the only mobile platform holder that could do this, and I’m surprised it took the company this long to integrate its retail operation into its mobile operation.

If you’re a developer and find yourself interested in the Mobile Associates API, you can learn more about it here. The API isn’t exclusive to the Amazon Appstore either as any Google Play app can integrate it as well.

[Image: AmazonAppDistro/YouTube]