App downloads in Amazons Appstore have grown more than 500 per cent year on year.

The figures were announced alongside the beta launch of a free A/B Testing capability, which enables Kindle Fire developers to test simultaneous treatments of their apps, and adjust based on customer learning data.

“Apps are living products continuously being updated, modified and improved, and with millions of potential active users, developers know that seemingly small changes can have a large impact on customers,” said Mike Frazzini, director of Amazon Games. “Our A/B Testing service is essential for developers because it will help offload the overhead costs of building, maintaining and running scalable tests.”

Amazon also announced that more apps are also incorporating its In-App Purchasing and GameCircle SDKs, with downloads more than doubling since the Kindle Fire HD launched in September. During October, 23 of the top 25 grossing apps in the Appstore used the In-App Purchasing technology.