Welcome
Hi, my name is Junseok Oh. Feel free to call me Jun.
This is my personal blog where I share thoughts on topics that interest me.
I’m a self-employed software engineer running my own business. My business focuses on mobile applications, plugins, and any small software buildable and maintainable by a solo developer or small team. These products address niche needs that only a small team or individual vendor can handle.
Outside of work, I’m a drawing enthusiast, knowledge lover, and, of course, engineer. One day, I want to create work that reflects my personality, tastes, and thought. For that, I’ve been thinking about how to integrate art and knowledge into my professional skills.
My Career and Skills in a Nutshell
Before going independent, I was an employee serving as a software engineer for almost 17 years.
I started my career at a mid-sized company located in Seoul, Korea. My first role was as a Windows Application Developer, and I later transitioned to a Spring-based Backend Engineer. I also worked with HTML, Javascript/JQuery, and ASP/JSP, though these skills are somewhat outdated now.
When I was living in Jeju Island, Korea, I worked at Kakao’s Web Search Team, developing a Web Crawler powered by Hadoop/HBase and Spring, running on hundreds of servers. This gave me hands-on experience with Large-Scale Distributed Systems handling petabyte-scale data.
My next and latest employer was Delivery Hero SE in Berlin, Germany. I worked at the Fintech team as a backend software engineer, developing PSP Connectors communicating with Payment Providers (such as Adyen, PayPal, etc) and the Payment Process Flow. My team and I adopted Microservices Architecture for loose coupling, independent scalability, and fast iteration.
Through my time at Delivery Hero, I’ve built hands-on experience with Java, Kotlin, Spring Boot, PostgreSQL, Kubernetes, Microservices, and Hexagonal Architecture.
