From a young age, Seungyong Lee had a knack for distilling a common thread from various pieces of information. No matter what he learned, he organized it more precisely than others and could explain it with clarity, as he could identify the underlying logical structure of seemingly different concepts. He enjoyed continuously learning and growing through this skill. Having loved math since childhood, he was introduced to coding in sixth grade and was immediately captivated. Coding problems often seemed easy to solve, and he would eagerly write and execute his code. However, things rarely worked as expected on the first try, leading him to modify and rerun his code repeatedly until it finally worked, which brought him immense joy. The short feedback loop and the feeling that “just a little more” would yield results perfectly suited his nature.

His interest in coding persisted through middle school. With few Korean coding resources available at the time, he discovered a website developed by Peking University that graded coding exercises. The problem was that the site was half in Chinese and half in English. So, he convinced the friend with the best English skills and another friend fluent in Chinese to study coding with him. Printing out exercises, he asked his friends to translate them so he could learn. He set a goal to solve at least six problems daily, coding for more than four hours each day. The enjoyment and immersion he felt were extraordinary, especially for a middle schooler. Even when he developed a pneumothorax and awaited surgery with a chest tube in place, he continued his coding studies and took exams online.

With his remarkable talent and exceptional dedication, Seungyong Lee grew into a highly skilled coder. Confident in his abilities by his third year of middle school, he entered the Informatics Olympiad, where he placed first at every level—from the regional preliminaries to the national finals. This success led to his selection as part of the Korean national team, winning a silver medal at the International Olympiad in Informatics (IOI). The exhilaration he felt at the IOI influenced him greatly, motivating him to continue studying coding.

Upon entering the Department of Computer Science at Seoul National University, Seungyong pondered how best to use his coding abilities. In his freshman year, he pursued this question by starting a business and developing a service, giving him three years of hands-on learning. Rediscovering the true enjoyment of coding, he had a pivotal realization during his third year while working for another company as part of a military service alternative. First, he gained confidence that he could create anything he wanted to in development; second, he decided that what he created had to fulfill a real need—he resolved to eventually found a company that would make something people truly need.

Identifying a need wasn’t difficult. Watching friends worry about coding tests for job applications confirmed a demand for coding education. He started teaching his friends, then opened a coding academy in Daechi-dong, where he taught friends, Olympiad students, and high schoolers. While focusing on each student, he grew more determined to provide a broader coding education service. He took courses in educational technology, philosophy, and psychology at Seoul National University to understand coding education from a larger perspective, ultimately deciding to start a coding education company. The timing was perfect, as COVID-19 was pushing education online, and his experiences with companies like Bank Salad and Lunit, which involved explosive growth, AI research, and evolving organizational structures, convinced him that the time was right. As a final validation, he spent six months teaching 50 students preparing for Samsung’s coding test using his curriculum, achieving impressive success rates.

When he founded CodeTree with ambitious plans for coding education, talented friends naturally gathered around him. Students he had taught at his academy joined him, saying, “No one can teach coding better than you,” and “This isn’t just product-driven but mission-driven, so it’s bound to succeed eventually.” Together with these exceptional colleagues, he is designing a curriculum to make coding accessible and enjoyable for everyone—a true “essence of coding” curriculum. The goal is to guide learners from beginner to independent coder, capable of achieving their coding goals without assistance. As he creates this service at CodeTree, he feels constant growth, taking joy in hearing from users who express gratitude for their improved skills.

For Seungyong Lee, CodeTree is much like coding itself. Coding education problems seemed solvable at first glance, but launching the service revealed challenges he hadn’t anticipated, requiring continual updates and testing—a process he and the CodeTree team find deeply enjoyable. Just as he eventually gained the confidence to create anything he wanted in development, CodeTree will ultimately create a curriculum that allows anyone to learn coding easily and enjoyably.