One 18-year-old Korean High School Girl’s Journey to 100k Installs on Her First Mobile App

She had never learned how to program. In less than a month, she pulled off this feat with her first mobile app — EXO-LIGHT.

Hyunsoo displaying her Android Application, EXO-LIGHT

On the morning of June 10th, I woke up looking forward to interviewing someone truly inspiring, Hyunsoo Si. Hyunsoo is an 18-year-old Korean high school student who achieved more than 100,000 installs and ranked #1 on Entertainment Category on her app “EXO-LIGHT” in the Google Play Store — all in less than a month.

What’s so fascinating about this? This was the first ever application she had ever created, and she didn’t use any funds marketing it.

What impressed me the most is that she has never learned how to program.


Hyunsoo’s Background

Hyunsoo is currently a senior at Jinmyeong Girl’s High School. Her high school is one of the few girl’s high schools in Korea that require students to take an elementary programming course in their first year.

However, these elementary programming courses don’t properly equip students with the tools to create applications. Rather than learning difficult languages like C and Java, they explore programming concepts with blocks.

Build Your Own Blocks (BYOB)

This course sparked Hyunsoo’s interest in programming, and she wanted to continue to learn more about it — so she founded a Programming Club at her high school.

Composed of non-programmers, the club learned from different high schools by hosting events. But unfortunately, because of the stress due to heavy schoolwork and a gradual loss of interest in programming, Hyunsoo disbanded the club. Hyunsoo told me:

“I thought I would like programming because I liked computers and block programming, but I knew I was wrong when I opened a book to learn about C, a complicated programming language.”

Motivation to Create EXO-LIGHT

Like many other girls her age, Hyunsoo is a big fan of the Korean Idol group, EXO.

Hyunsoo was very stressed while she was planning to attend her first EXO concert with her friends. The total cost was too burdensome for a student like her. A ticket to the concert costs $120, and after factoring in transportation and lightsticks for the concert, the total cost for each person would be around 200$.

Hyunsoo’s best friend is a huge fan of EXO, too, and although she wanted to support the band and buy the lightsticks to have the full concert experience, she didn’t have the extra money to spend another $35 on a glowing lightstick.

An EXO Light stick, which costs up to $43 on eBay

The lightsticks are upgraded every concert season, so buying a secondhand one from a previous performance season would be less meaningful. This was a problem not only to Hyunsoo’s friend, but also to many other people who couldn’t afford to purchase a new lightstick every season.

Hyunsoo had an idea to design a smartphone application that would resemble the lightsticks on her phone screen, so that people without the lightsticks could fully enjoy the EXO concert experience as well.

Her Steps to Create An App

In her spare time, Hyunsoo loves brainstorming new ideas. She wanted to make her ideas a reality, but since she barely knows any programming, she looked for a simple way to create her own applications.

The first thing she did was to open the Play Store and search:

“App to create apps”

After trying more than six different app creating applications, she downloaded Sketchware, a user-friendly mobile development tool for creating Android Applications.

Sketchware on Play Store

Hyunsoo said that other applications overloaded her with way too much information, which made the programming process very overwhelming. Sketchware’s user-focused, simplified interface helped her see that Sketchware’s designers really cared about the user experience for people like her.

Other applications provide a fixed template that limits how users can think and create; however, Sketchware provides programming blocks that enable one’s imagination to go wild. The blocks were labeled with names identical to their actual programming functions, so it was easier to Google the blocks’ functionalities.

Despite the freedom the app provided, there were still challenges Hyunsoo faced.

It was really difficult for Hyunsoo to upload her application to the Play Store, since she’s never done it before. It was a big commitment for her to pay $25 and purchase a Google Developer Account.

Sketchware Experience

Playing around with Sketchware, Hyunsoo was able to create the EXO-LIGHT application in 3 days and upload it to the Play Store. She didn’t expect her application to go so viral, but her application received nearly 22,000 installs on its first day.

The app’s reviews demonstrate that people are looking for such an application and appreciate Hyunsoo’s EXO-LIGHT. Through user feedbacks and reviews, Hyunsoo is planning to update the application with additional features, after she is done with her finals.

EXO-LIGHT currently has over 110,000 installs with about 3,500 reviews and a 4.9 rating. Her application was for a while ranked 6th in the Chinese Play Store’s Entertainment Category, and 9th in Indonesia’s.

Future Plans

Hyunsoo is communicating with fans from other states to improve her application for more users, and she hopes that EXO-LIGHT will be used in future concerts.

When she is done with this project, she wants to tackle other applications. For example, Hyunsoo wants to build an app that can track which library seats are open at her school. Also, she is very interested in using public information API’s, for uses such as retrieving weather and bus stop information.

Eventually, she wants to create her own start-up in the future. I would like to thank Hyunsoo for her time for this interview and for sharing her exciting story.


Download Links

Check out Hyunsoo’s EXO-LIGHT application in the Google Play Store:

As well as Sketchware she used to create EXO-LIGHT:

Want to know more about Sketchware? Check out their Facebook page here.