When you purchase your smartphone most usually hit up the corresponding app store to download whichever apps take their fancy, whether that be the Android Market, BlackBerry App World, or Apple App Store, or other. However the app download market isn’t the biggest, as the app development market is already twice as big.

The app development market includes such thing as app creation, distribution, management along with extension services, and according to a new report by Research2guidance, the app development market will grow to hit $100 billion US in 2015.

In just a year and a half since the launch of the Apple iOS App Store, the app development market has overtaken the app download market when it comes to revenue.

The quantity of apps developed by 3rd-party app developers comes to 66 percent of all apps, a share that will apparently increase over the coming years as more companies want to publish apps but do not have the in-house resources.

Senior research analyst for Research2guidance, Egle Mikalaiunaite says, “With increasing smartphone and application penetration, companies have a vital need to be in this market and fuel the demand for app development services.”

Apparently most developers start out as publishers, but due to the hard level of competition with the main app stores along with failure rates, more app developers are changing their business model and concentrating on developing apps for 3rd-parties rather than creating their own apps.

Research Director ay Research2guidance, Ralf-Gordon Jahns, describes it as, “Selling the spades became a much more reliable and bigger business than digging for the gold.”

Currently most app project revenue comes via app creation services such as design, concept creation, and coding and in 2010 app maintenance, distribution, analytics, and extension services accounted for just 2 percent of earnings.

Research analyst Daniel Meehan explained, “The need for additional services is growing and this share will grow significantly between now and 2015. However, app development will remain the core part of app project costs.”

According to a sample of the “selling spades for gold diggers” report, which can be viewed here, iOS and Android are by far the most prominent platforms amongst the mobile app developers, and with the launch of the Apple Developer Kit (SDK) new garage developer with little experience in app development and mobile content rushed into the market with most initially developing their own apps but soon realised that developing for 3rd-parties delivers a more secure revenue stream.