When Mr Calixto Tay Wei Kiat graduated with the highest distinction from Singapore Management University three years ago, a multinational tech company offered him a job with a starting pay of $7,000. He turned it down.
"I did not want to regret not exploring my own path, and trying things out on my own first," he said.
Today, Mr Tay, 28, who studied information systems management, is co-founder of mobile app development house Originally Us. It has created more than 30 apps for clients since it started in 2014.
One of its most successful apps is SG BusLeh, which gives the arrival times and locations of buses.The free app has almost 200,000 downloads and is the third highest-rated transportation app in the Android store here, after Grab and Uber.
Originally Us is now making profits and has 10 staff, including those at its Vietnam office, which opened last year.
"My goal now is to build something that can reach out and impact more people, even overseas," said Mr Tay, who picked the name Calixto as his wife is called Calista.
His interest in software design started at the then Chinese High School, where students had to learn programming. He developed a program like Google Docs to enable his classmates and him to edit the same document at the same time.
"Learning to code allows us to use technology to solve a specific problem - not just for you, but for the people around you who face the same problem," he said.
In 2014, Mr Tay won the IT Youth Award, given by the Singapore Computer Society, for Oompr!, a social marketplace which has since closed down.
His latest app is HoiPOS, a mobile point-of-sale (POS) system for food and beverage establishments which collects data such as the average time required to prepare each food item. "We wanted to create a POS system which gives insights to help businesses make better decisions, such as in allocating their labour and resources," he said.
The app is used by Caffebene, a South Korean cafe chain that has a store at VivoCity.
An interest in coding has served Mr Tay well. He said: "Coding may be seen as something nerdy, or uncool. But increasingly, with the prevalence of the smartphone and the Internet, we see the value and impact it has in solving problems in everyday life."