San Jose: For the second year in a row, the youngest developer at Apple's Worldwide Developer Conference (WWDC) has made the long journey to be here from Melbourne, Australia. Yuma Soerianto, 10, was one of a handful of people around the world to win a scholarship to attend.

Soerianto has been building websites since he was six years old, but last year turned his attention to the App Store.

"I liked building websites, just basic coding using javascript and css," he tells Fairfax Media, "but everyone has phones, so I wanted to learn how to build apps. And I could build more fun stuff on an iPhone, like games!"

Soerianto is self taught. He began coding using Swift Playgrounds, the iPad app Apple debuted at last year's conference. Swift Playgrounds is designed to teach children the fundamentals of coding in an interactive environment. It relies on gaming mechanics and friendly-looking cartoon characters to keep children engaged.

Soerianto quickly completed the tutorials in Swift Playgrounds, and knew he wanted to build his own app. He turned to his parents and teachers for further learning, but sensed he knew more about coding than they did. So he enrolled in a free iTunes U Swift coding course, offered by Stanford University.

Less than a year after completing the course, Soerianto has released five apps on the App Store, including Lets Stack!, Hunger Button, Kid Calculator, Weather Duck and Pocket Poké. Let's Stack! Is Soerianto's most complex app to date. You play as a construction worker, who just happens to be a duck, building an increasingly narrow tower block.

When asked how long it took to code, Soerianto says "about two months", before quickly qualifying: "But that's because I was building it around school work, and I took two weeks off to work on my application for the WWDC scholarship."

So what's next for Soerianto?

"I actually made an app on the plane!" he says, pulling out an iPhone. He used the 14-hour flight to build a tip calculator for his parents to use during their stay in San Jose.

"You put in how much the total is, and then how much of a tip you want to leave. The app also shows you how much the total is in Australian dollars. I had to update it when we got here, because prices here don't include tax. So now it adds in the tax, too."

And what does Soerianto want to be when he grows up?

"Batman." he answers. "That's a joke, by the way. I really want to teach people how easy it is to code."

To that end, Soerianto has started a YouTube channel, Anyone Can Code. The channel has over five hundred subscribers and counting.

"The funny thing is, I made the YouTube channel for other kids, but most of the people who comment on my videos seem to be adults", he says.

When asked if there was anything he was hoping to see during his week at WWDC, Soerianto pauses for a moment, then says "I'd really like to meet (Apple CEO) Tim Cook."

As if on cue, Cook wanders into the hall to meet the scholarship winners, and his first stop is Soerianto's table. After a few minutes chatting with Cook, Soerianto returns, a little star struck.

"Did you see that?", he says. "That was Tim Cook. That was pretty cool."

The author travelled to San Jose as a guest of Apple.