The iPad may lead in the tablet war, but Amazon (NASDAQ:AMZN) is charging hard to keep pace.

The online tech and retail giant announced, as part of a press release today, that mobile app downloads from Amazon's Appstore have increased by 500% over the past year. While Amazon has relatively fewer apps than competitors -- its Appstore only breached the 50,000-app mark in September, whereas Google's (NASDAQ:GOOGL) Android Market (now Google Play) boasted more than 400,000 worldwide apps in February -- it's an important metric of growth for the company.

Amazon launched the Appstore back in March 2011, but the company's release of its Kindle Fire tablet in late 2011 has offered an exclusive market for apps. (Amazon's Appstore is also available on Android devices.) The company has also taken steps to help app developers: The app growth number was only part of the larger press release focusing on the company's launch of new A/B testing for developers to test and adjust apps, while receiving data about what modifications have worked best.

The press release also included several other newsworthy items, including a note that developers with In-App Purchasing loaded into their apps more than doubled in Q3 2012.

Dan Carroll has no positions in the stocks mentioned above. The Motley Fool owns shares of Amazon.com and Google. Motley Fool newsletter services recommend Amazon.com and Google. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.