Djay is one of Apple's favorite apps. The dj-ing software was demoed onstage at the iPad 2 launch, won Apple's coveted Apple Design Award in 2011, and has won Apple's App of the Year award in over 100 countries. Djay is so well-liked that it's even pre-installed on many of Apple's demo units in store. These are privileges and accolades afforded only to the apps that best show off the performance that ostensibly only Apple products can offer. And until recently, that might have actually been the case. But today, Djay's launching on Android.

"I don't think Android users are cheaper."

Android users will love Djay — but the app's departure from Apple exclusivity potentially signals a bigger trend. A few years ago, nearly all of the best indie apps and venture-backed startup apps were launching exclusively, or at least first, on iPhone. That's still largely the case, but according to Djay creator and Algoriddim CEO Karim Morsy, the tides are shifting. Android is no longer a luxury — it's a requirement if you want to even scratch the surface of reaching an audience outside the United States.

With the launch of Android 4.0 Ice Cream Sandwich three years ago, Algoriddim began adapting Djay for Android. But Android still didn't seem quite ready yet. "Apple has been developing its developer tools for years, so it's a very clean and streamlined process," says Morsy. "Android has definitely gotten better, but its Java, C++, etc. mixture of different programming languages makes the whole process just more complicated." Development on iOS is also inherently a lot more predictable, he points out, since Apple owns the entire hardware and software experience. Some of Morsy's iOS developers started working on the project, but ultimately Algoriddim had to hire four dedicated Android engineers for the project (to match Algoriddim's six for Mac / iOS).

With the launch of Android KitKat and the Android L Developer Preview, Algoriddim finally kicked development into high gear. Much of the team's new work revolved around rewriting the app to work on the variety of processors and screens sizes present on the hundreds of Android smartphones out there. "It's all about avoiding audio dropouts and your eye seeing glitches, since the eyes and ears aren't very forgiving," says Morsy. "We had to do this for almost all the [Android] phones." Now, almost every user interface element, from spinning records to beat pads, is dynamic for different screen sizes. "It's quite easy to make a great Android app that's a simple table view," says Morsy, "but we're basically processing 44,000 audio frames per second, per deck. So that's 88,000 frames per second, plus all the stuff on the screen."

"It's quite easy to make a great Android app that's a simple table view."

Developing for the Nexus 5 and other newer devices made development simpler. The recent Nexus devices, Morsy says, include a feature called FastPath that handles audio optimization to reach lower latency. But, many barriers still exist to making high-fidelity Android apps. For example, Android includes no built-in support for outputting to MIDI devices like turntables and keyboards, Morsy says. "On iOS there's CoreMidi, which is a framework to process MIDI packets and interface with MIDI devices, and that's been around on Mac forever," he says. "We had to do the whole MIDI integration ourselves on Android, which took several months by itself."

Building for Android is difficult and requires resources, Morsy says, but reaching an entire world of people is a compelling enough reason to make it happen. In the United States, Apple's market share is close to 45 percent, but globally, it's just 15 percent (to Android's 85 percent). "The vision of the company was to make DJ-ing accessible to every customer," says Morsy. "To pursue that mission, we need to expand." With a proper framework in place, Morsy says Algoriddim can now keep all of its apps at parity, and hopefully make a lot more money. A quick look at the charts shows that while App Store revenues still exceed Google Play's, Google's store is rapidly gaining momentum. Unfortunately for Djay, however, Apple is notoriously sensitive about which apps it chooses to feature. The company could pull Djay from its Apple Store demo units.

Many of Apple's top developers have been content targeting a small, premium niche within the App Store, but according to Morsy, even some of these premium developers should consider expanding their reach. After years of living in the App Store, perhaps some companies like Algoriddim and others think they've reached their maximum addressable market in the App Store. "I don't think Android users are cheaper," he says. "It's really about the quality of the app." However, investing in potentially doubling your team to expand on Android is still risky. But if Djay is indeed one of the first of many "big indies" to make the move, it could potentially spell trouble for the incredible app dominance Apple has exhibited.