Can you believe that it’s already been over a year since Amazon introduced their Appstore for Android? In that time, it’s grown into a formidable service that has proven to be even more profitable than Google Play. We recently had a chance to talk with Aaron Rubenson, director of Amazon Appstore for Android, about the evolution of the Appstore and why developers should be developing for them.

Rubenson started out by telling us that the Appstore wasn’t just a split-second decision made in 2011. They actually had the infrastructure and tools since the launch of Amazon Web Services in 2002. They even started dabbling in mobile development with the AWS SDK before they launched the Appstore. None of that has changed. Developers can still utilize AWS for mobile applications. In fact, Amazon encourages it alongside their other mobile specific SDKs for apps.

You’d be forgiven for not knowing about Amazon’s mobile presence before 2011 though. They didn’t really make their mark until the launch of the Amazon Appstore for Android in March 2011. Rubenson told us that there were around 4,000 apps when it launched. That number has now increased to 51,000.

Over 50,000 apps in just a year is nothing to sneeze at, but it’s relative newcomer status puts it at a disadvantage to the hundreds of thousands apps that are available to consumers on Google Play. How does Amazon compete (and win) against a store outnumbers it almost 12-to-1? Rubenson told us that a number of programs and incentives that are exclusive to the Amazon Appstore help drive installs and downloads.

First and foremost, Amazon is still the only Appstore that offers anything like Test Drive. If you’re not familiar, it’s a program that lets users play around with an app in their browser. It’s a try before you buy service that doesn’t even require the user to install the app, and it’s proven popular among consumers and developers. Rubenson said that Test Drive has accumulated over 7.7 million minutes of use across the 19,000 apps that are currently enrolled in the program.

Since the launch of the Appstore, Amazon has also featured the Free App of the Day. Rubenson said that there have now been over 375 free apps on offer through Amazon. All those free apps also represent $1,100 in value. It’s that kind of promotion that turns heads and converts consumers into loyal users. One fan told us that he had the Amazon Appstore installed on all of his devices and checks the Free App of the Day religiously. That’s the kind of loyalty that the Amazon Appstore inspires. Rubenson hopes that developers will see that and get their apps on the service.

Speaking of developers, Rubenson most of our time together explaining why he thinks the Amazon Appstore is the best platform for Android developers. The robust set of tools that Amazon has on offer to developers is definitely a plus, but he thinks the real advantage comes in the form of Kindle.

The Kindle Fire, and its new HD cousin, are what’s driving a lot of the growth in the Amazon Appstore. One reason for that was the launch of the in-app purchasing SDK that allowed developers to offer free-to-play titles with microtransactions on the Amazon Appstore. Rubenson claimed that in-app purchases were generating twice as much revenue as those apps that only feature an up-front transaction to purchase. He pointed out that the SDK is also developer friendly as it only takes about 10 minutes to implement it into apps.

The Kindle is also pushing Amazon Appstore even deeper into the realms of gaming apps with the launch of GameCircle in July. It’s a set of tools that allows developers to add social and competitive features to their games. He couldn’t provide exact numbers, but Rubenson said that many developers have expressed interest in GameCircle. He also said that a number of the most popular games on the Amazon Appstore have integrated GameCircle.

All these tools and features are great, but they don’t mean anything without a good discoverability plan. I told Rubenson about the frustration that I’ve been hearing from developers in regards to getting discovered on app stores. A recent study even said that over two-thirds of all apps on iTunes are never downloaded. People mostly stick to the top 20 apps and stay there. He said that this is where Amazon is different.

He told us that the trust consumers put into Amazon carries over to people shopping on the Amazon Appstore. They’re encouraged to go deeper into the recesses, past the top 20 apps, to find the diamond in the rough. They accomplish this in a number of ways. First, they make sure to test every app before it hits the App Store. It’s not just a simple approval process, but rather a strict test to see that each app meets all the guidelines that Amazon has set for its Appstore. The strict process guarantees that users can trust every app to work on a fundamental level.

The big advantage they have over others, however, relates to Amazon’s power as a retail giant. They have curated an advanced recommendation system over the years that has carried over to the Appstore as well. App pages will list a number of other apps based upon the interests that a customer has expressed in their shopping patterns. It’s the kind of exposure that nobody else can offer.

For their part, Amazon is working hard to bring more developers over to their side. Rubenson told us that Amazon has a team that will work one-on-one with developers to bring their apps to market. They will help developers in making, marketing, placement and all other avenues to make sure that each app has all the chances it can get to succeed.

During our time with Rubenson, it was obvious that Amazon cares about developers. The company is giving developers all the tools they need to not only compete, but thrive, in the highly competitive Android app market. Add in the Kindle Fire HD to the equation and you have a company that stands to emerge as the biggest app player on the market.