One of the key tools for online marketing has always been A/B testing, enabling marketers to use the flexibility of the web to rapidly test and improve ads, offers, layouts, etc.

Now Amazon has announced that it is launching a new A/B testing feature on its Amazon app platform, with the goal of attracting more Android developers to bring their apps to Amazon’s platform.

With this new A/B testing feature, developers can upload apps with slightly different features or variables to the Amazon platform. Consumers can download and use the apps, and the developers can see how well each version performs in the market. They can then go back select the best version or tweak a version once they have picked up the learning’s from their customer base.

Most developers currently use third party A/B testing in order to test their app, but they will now be able to do this for free as long as they distribute their app via the Amazon platform. And it will allow them to iterate much more quickly, which can make development more effective.

This move is also a bit of a shot at Apple’s App Store, which had developed a reputation for being sometimes slow and difficult to deal with. Apple insists on reviewing all new apps or upgrades, which can cause delays for developers and discourage them from very aggressive, fast paced A/B testing cycles.

“Our A/B Testing service is essential for developers because it will help offload the overhead costs of building, maintaining and running scalable tests,” said Mike Frazzini, Director of Amazon Games, in a statement released this morning. “We’ve drawn from our years of experience conducting and refining our own A/B testing on Amazon.com to bring developers a testing product that will give them the capability to perfect their apps, retain customers, and grow their business.”

As part of the announcement Amazon announced a few metrics showing that their platform is growing with downloads growing by 500% year on year. According to App store analytics firm Distimo, Amazon’s platform now has nearly 60,000 applications available for download, from over 15,000 developers.