The app applies colourful filters to photos and has had “a couple hundred” downloads since it first launched about 2 weeks ago. “It's a little early to say if it successful or not - I'm hoping that people will like my app and enjoy using it,” she said. Some kids making apps aren't even in their teens. Thomas Suarez of South Bay in the US, 12, delivered an inspirational talk at the TEDxManhattanBeach conference in October, showing how he had set-up his own company, CarrotCorp, and made two apps that are currently on iTunes: Earth Fortune, which displays the Earth in different colours depending on what your fortune is, and Bustin Jieber, a Whac-a-Mole game for Justin Bieber. The 99 cent Bustin Jieber app is his “favourite and most successful app”, he said. Thomas also sells a number of other Whac-a-Mole games such as Bustin Howie and Bustin Piers. “A lot of kids these days like to play games, but now they want to make them,” Thomas said. “And it's difficult because not many kids know where to go to find out how to make a program…and not many parents have written apps.” Thomas therefore decided to start an app club at school where any student could learn how to design an app.

Not long ago another young man, Robert Nay of Utah in the US, 14, unveiled his free app Bubble Ball, which has since had more than 9.1 million downloads. It's a “physics puzzle game, where you will test your ingenuity and thinking skills to get the bubble to the goal”. At one point it was rating even higher in the free app charts than the popular Angry Birds game. Robert's app makes money from what is known as an “in-app” purchase, which gives users 23 bonus levels should they wish to have access to them for 99 cents. The app was the result of peer pressure and some serious after-school dedication. "Since [his friends] know Robert's good with computers, they suggested that he should make one," Robert's mother, Kari, told ABC News in January. Robert accepted their challenge and went to the public library to investigate programs that would help him build his game.

Matthew Lesh of Malvern in Victoria, 18, started work on his first app iTweetReply - which sold for $1.99 a pop - when he was 15 with the help of two other teens in Sydney, Matthew Roberts and Tom Ricciardiello, both 17. The app sent alerts to users about tweets they had received on the micro-blogging site Twitter before any other app could do so. Since then the trio have sold their app business to a UK company for “thousands”, Lesh said. Syncode, the company behind Matthew's iTweetReply and other apps (Synotes and Syncopy), sold “thousands” of dollars worth of apps when run by him and his Sydney co-founders, Lesh said. “The apps had their ups and down financially,” he said. “They made a little bit of money, but if divided by the hours worked on them we would have been better to get a job at McDonald's. Personally my experiences with app development [was that it was] more of a hobby than a career path, however I have considered such an option.” Ebony said she became interested in smartphone apps after getting an iPhone earlier this year and looked into becoming a developer. “I've been interested in web design [and] development for about 5 years now,” she said. “I made Lomo Ho for myself (or at least for my age group) ... [and] just wanted something that was easy-to-use and would post quick, cool images to social networking sites when you are out and about.” It took her four and a half months to create and she's now working on another photography app which has taken about 2 weeks to make and will launch soon. “I can definitely see myself making a career out of developing apps,” she said. “I really enjoy [making them] and I have at least a dozen more ideas for apps which should keep me busy for awhile.”

Brandon Cowan, 17, a student at Masada College in Sydney's North Shore, developed the $2.99 iParkedHere app with family friend Hilton Rosenfeld. The app helps users remember exactly where they have parked their car and warns them when their parking time has run out. In an interview on April 5 this year, Brandon said his then $2.49 app was the No.1 top grossing app in the Lifestyle category on the iTunes app store and ranked 31st out of all apps on the Australian store that day. He would not reveal revenue figures but, to break into the top 10 apps, one needs to be selling hundreds of copies a day. At the moment Brandon's keeping the money he earns from sales in the company but has said previously that he will probably be saving it for a house when he gets older. Another student from NSW, Conner Brendish, 18, helped create the $4.49 iSpoke Flash Cards, an interactive flash cards app which gives users the ability to create their own flash cards, store them in albums and record or overdub their own voice. It was designed as an educational tool for children with special needs. Anthony Toben, a parent frustrated with the technology available to assist and treat autism for his son Joshua, got Brendish to make it. From the proceeds, 50 cents of each sale is donated to Autism Spectrum Australia.

Another top-selling application, made by a 16-year-old Melbourne student and based on a comedian's impersonation of the criminal Mark ''Chopper'' Read, triggered a legal fight. When it was available last year the app - Chopper Soundboard - was described on the iTunes store as containing audio files from the sketch comedy created by Heath Franklin for The Ronnie Johns Half Hour. That sketch poked fun at the habits of ''soft'' city dwellers, such as the preference for soy milk in coffee, and was popular with teenage boys. It was the highest selling ''entertainment'' app in the country in June last year, and the fifth-highest-selling overall. It sold at least 10,000 copies at $1.19 each in the three weeks before it was pulled from sale due to the copyright dispute. The show was produced by Jigsaw Entertainment and aired on Channel Ten in 2005 and 2006, which is now suing Apple, not the boy, claiming the company breached copyright. Jigsaw claims the student, who has previously asked for his identity be kept secret, made the app using up to 116 sound bites, with many taken from the sketch titled ''Harden the F--- Up''. Jigsaw also claims the student did not seek permission before using the sound bites. The next hearing of the case is on Monday.

International army of teens The Australians joins an international army of teens developing apps. One 16-year-old from Phoenix, Arizona in the US, Nick Garcia, claims to have turned over $US100,000 in revenue from his apps and YouTube videos, recently posting screenshots of earnings from his Apple developer account showing he was owed more than $US8600 by Apple. He also said he made about $US20 to $US30 a day from ads on Google video sharing website YouTube. Answering questions on the social news website Reddit.com, Garcia said most of his apps were “garbage”. But despite this - and perhaps more important for him - they sell well. Some of the popular apps he sells on the iTunes store include Caffein Meter, an app which uses the iPhone's accelerometer to measure how much a user is shaking to tell them if they have had too much caffein. Another is Ultimate Vuvuzela 2010, a virtual vuvuzela.

His parents are “very proud” and were “sort of shocked” at the first payment he got from Apple, he said. “They're really proud that I was able to do this so early.” Most of the money he makes he saves but if there's something interesting or cool he wants he will usually purchase it. The cool things Nick said he spent his money on included the recent purchase of a car as well as sound systems, furniture for his room, computers, a new TV and skateboard gear. He also pays his own iPhone bill. “I almost always get the newest iPhone or iPad the day it comes out,” he added on Reddit.com. Another teen from Scarborough in the United Kingdom, James Shaw, 16, has a portfolio of about 16 apps on Apple's iTunes store. “I read an article in a UK newspaper about a 20 year old who had created an iPhone app and profited around $1,000,000 from it in the first year alone,” he said. “I imagined myself being in that position when I'm 20 and have been motivated ever since to succeed. Hopefully one day I will become as successful as him.” James, who started learning Objective C (the software language) in May 2009, had learnt enough to publish his first app on the Apple iTunes app store on December 14 2009.

Most of James's apps feature the ability to find things and sell for 99 cents in Australia. One of his apps, Bank Finder, searches for banks in your local area using an iPhone or iPad's built-in GPS and displays it on an easy-to-use map. There's also Coffee Finder!, Fuel Finder, Hotel Finder!, Pizza Finder, Post Office Finder, Restaurant Finder! and Toilet Finder! that all offer a similar service - searching for each place listed in their title nearby. On average James said he spent about 40 hours working on an app. “Each app is different depending on it's complexity.” Although he admits his apps haven't been worldwide phenomenons such as Doodle Jump or Angry Birds, which have each sold about 20 million copies, he said he was “very pleased” with what he had achieved so far. “I have sold around 12,000 units over the 2 year period that I have been on the app store,” he said. “I will definitely continue to make apps in the foreseeable future and have some ideas in the pipeline.” He enjoyed making apps and said it was “an added bonus” that he happened to make “a bit of money” out of selling them. “If I managed to think of several new, innovative app ideas then I could definitely see myself making a career out of app development,” he said. The extra income would come in handy to pay for the next step in his education, he said, commenting on the high cost of UK university tuition fees, saying they were “expensive”.

Learning how to code was the most difficult part for James. “You can be staring at one line of code for hours figuring out why it isn't working so therefore you have to be patient and motivated to succeed,” he said. “You need to be creative and have lots of ideas as with 500,000+ apps available for download on the [iTunes] app store, you need to stand out from the crowd.” Marc Edwards, founder and lead designer at Bjango, developers of Apple apps including Consume, Phases and Beats, was amazed at what young kids were doing with apps. “It's great to see these guys succeed,” he said. “They're getting a huge jump start in life, learning skills others may never have. What's best is that it's been done independently, motivated by a desire to explore and learn.” He said apps for Apple devices like the iPad and iPhone were incredibly difficult to build. “Far harder than an equivalent website,” he said. “To get an app on the App Store—any half decent app—is a big accomplishment.” Mr Edwards also said getting noticed was even harder than building a decent app. “There may be over 200 million [iPad, iPhone and iPod Touch] devices sold, but there's also 500,000 apps competing for attention. About 20,000 apps were released in October 2011. That's well over 700 a day. It's an avalanche.”

Becoming an app developer was “absolutely” a sustainable way to earn a living, he added. “There's a massive industry that has grown around the [Apple] and Android app stores. If you can build and release a hit, you shouldn't have any trouble paying the rent.” Loading - With The Guardian and Vanda Carson This reporter is on Facebook: /bengrubb